Update URLs from `master` to `main` branch. (#2335)

diff --git a/docs/GetStarted/getting_started_linux_bazel.md b/docs/GetStarted/getting_started_linux_bazel.md
index 738a365..8d4a9dc 100644
--- a/docs/GetStarted/getting_started_linux_bazel.md
+++ b/docs/GetStarted/getting_started_linux_bazel.md

@@ -20,7 +20,7 @@
 ### Install Bazel
 
 Install Bazel version > 2.0.0 (see
-[`.bazelversion`](https://github.com/google/iree/blob/master/.bazelversion) for
+[`.bazelversion`](https://github.com/google/iree/blob/main/.bazelversion) for
 the specific version IREE uses) by following the
 [official docs](https://docs.bazel.build/versions/master/install.html).
 
@@ -112,7 +112,7 @@
 ```
 
 Translate a
-[MLIR file](https://github.com/google/iree/blob/master/iree/tools/test/simple.mlir)
+[MLIR file](https://github.com/google/iree/blob/main/iree/tools/test/simple.mlir)
 and execute a function in the compiled module:
 
 ```shell

diff --git a/docs/GetStarted/getting_started_linux_cmake.md b/docs/GetStarted/getting_started_linux_cmake.md
index ed7856e..70da146 100644
--- a/docs/GetStarted/getting_started_linux_cmake.md
+++ b/docs/GetStarted/getting_started_linux_cmake.md

@@ -77,7 +77,7 @@
 
 > Tip:<br>
 > &nbsp;&nbsp;&nbsp;&nbsp;The root
-> [CMakeLists.txt](https://github.com/google/iree/blob/master/CMakeLists.txt)
+> [CMakeLists.txt](https://github.com/google/iree/blob/main/CMakeLists.txt)
 > file has options for configuring which parts of the project to enable.<br>
 > &nbsp;&nbsp;&nbsp;&nbsp;These are further documented in [CMake Options and Variables](cmake_options_and_variables.md).
 
@@ -99,7 +99,7 @@
 ```
 
 Translate a
-[MLIR file](https://github.com/google/iree/blob/master/iree/tools/test/simple.mlir)
+[MLIR file](https://github.com/google/iree/blob/main/iree/tools/test/simple.mlir)
 and execute a function in the compiled module:
 
 ```shell

diff --git a/docs/GetStarted/getting_started_linux_vulkan.md b/docs/GetStarted/getting_started_linux_vulkan.md
index 9ee8c61..5a0fd7f 100644
--- a/docs/GetStarted/getting_started_linux_vulkan.md
+++ b/docs/GetStarted/getting_started_linux_vulkan.md

@@ -39,7 +39,7 @@
 ### Quick Start
 
 The
-[dynamic_symbols_test](https://github.com/google/iree/blob/master/iree/hal/vulkan/dynamic_symbols_test.cc)
+[dynamic_symbols_test](https://github.com/google/iree/blob/main/iree/hal/vulkan/dynamic_symbols_test.cc)
 checks if the Vulkan loader and a valid ICD are accessible.
 
 Run the test:
@@ -58,7 +58,7 @@
 HAL, which includes checking for supported layers and extensions.
 
 Run the
-[device creation test](https://github.com/google/iree/blob/master/iree/hal/cts/device_creation_test.cc):
+[device creation test](https://github.com/google/iree/blob/main/iree/hal/cts/device_creation_test.cc):
 
 ```shell
 # -- CMake --
@@ -79,7 +79,7 @@
 SwiftShader's Vulkan ICD (Installable Client Driver).
 
 IREE has a
-[helper script](https://github.com/google/iree/blob/master/build_tools/third_party/swiftshader/build_vk_swiftshader.sh)
+[helper script](https://github.com/google/iree/blob/main/build_tools/third_party/swiftshader/build_vk_swiftshader.sh)
 for building SwiftShader from source using CMake:
 
 ```shell

diff --git a/docs/GetStarted/getting_started_macos_bazel.md b/docs/GetStarted/getting_started_macos_bazel.md
index a169f8d..2b285eb 100644
--- a/docs/GetStarted/getting_started_macos_bazel.md
+++ b/docs/GetStarted/getting_started_macos_bazel.md

@@ -115,7 +115,7 @@
 ```
 
 Translate a
-[MLIR file](https://github.com/google/iree/blob/master/iree/tools/test/simple.mlir)
+[MLIR file](https://github.com/google/iree/blob/main/iree/tools/test/simple.mlir)
 and execute a function in the compiled module:
 
 ```shell

diff --git a/docs/GetStarted/getting_started_macos_cmake.md b/docs/GetStarted/getting_started_macos_cmake.md
index 59d22e8..51ef0ab 100644
--- a/docs/GetStarted/getting_started_macos_cmake.md
+++ b/docs/GetStarted/getting_started_macos_cmake.md

@@ -77,7 +77,7 @@
 
 > Tip:<br>
 > &nbsp;&nbsp;&nbsp;&nbsp;The root
-> [CMakeLists.txt](https://github.com/google/iree/blob/master/CMakeLists.txt)
+> [CMakeLists.txt](https://github.com/google/iree/blob/main/CMakeLists.txt)
 > file has options for configuring which parts of the project to enable.<br>
 > &nbsp;&nbsp;&nbsp;&nbsp;These are further documented in [CMake Options and Variables](cmake_options_and_variables.md).
 
@@ -99,7 +99,7 @@
 ```
 
 Translate a
-[MLIR file](https://github.com/google/iree/blob/master/iree/tools/test/simple.mlir)
+[MLIR file](https://github.com/google/iree/blob/main/iree/tools/test/simple.mlir)
 and execute a function in the compiled module:
 
 ```shell

diff --git a/docs/GetStarted/getting_started_python.md b/docs/GetStarted/getting_started_python.md
index 627dd3d..1a0452b 100644
--- a/docs/GetStarted/getting_started_python.md
+++ b/docs/GetStarted/getting_started_python.md

@@ -61,9 +61,9 @@
 ## Using Colab
 
 See
-[start_colab_kernel.py](https://github.com/google/iree/blob/master/colab/start_colab_kernel.py)
+[start_colab_kernel.py](https://github.com/google/iree/blob/main/colab/start_colab_kernel.py)
 and
-[Using Colab](https://github.com/google/iree/blob/master/docs/using_colab.md)
+[Using Colab](https://github.com/google/iree/blob/main/docs/using_colab.md)
 for setup instructions, then take a look through the
-[Colab directory](https://github.com/google/iree/tree/master/colab) for some
+[Colab directory](https://github.com/google/iree/tree/main/colab) for some
 sample notebooks.

diff --git a/docs/GetStarted/getting_started_windows_bazel.md b/docs/GetStarted/getting_started_windows_bazel.md
index 3eb660d..d3f01c3 100644
--- a/docs/GetStarted/getting_started_windows_bazel.md
+++ b/docs/GetStarted/getting_started_windows_bazel.md

@@ -25,7 +25,7 @@
 ### Install Bazel
 
 Install Bazel version > 2.0.0 (see
-[`.bazelversion`](https://github.com/google/iree/blob/master/.bazelversion) for
+[`.bazelversion`](https://github.com/google/iree/blob/main/.bazelversion) for
 the specific version IREE uses) by following the
 [official docs](https://docs.bazel.build/versions/master/install-windows.html).
 
@@ -108,7 +108,7 @@
 ```
 
 Translate a
-[MLIR file](https://github.com/google/iree/blob/master/iree/tools/test/simple.mlir)
+[MLIR file](https://github.com/google/iree/blob/main/iree/tools/test/simple.mlir)
 and execute a function in the compiled module:
 
 ```powershell

diff --git a/docs/GetStarted/getting_started_windows_cmake.md b/docs/GetStarted/getting_started_windows_cmake.md
index 77d4fe4..dcab418 100644
--- a/docs/GetStarted/getting_started_windows_cmake.md
+++ b/docs/GetStarted/getting_started_windows_cmake.md

@@ -75,7 +75,7 @@
 
 > Tip:<br>
 > &nbsp;&nbsp;&nbsp;&nbsp;The root
-> [CMakeLists.txt](https://github.com/google/iree/blob/master/CMakeLists.txt)
+> [CMakeLists.txt](https://github.com/google/iree/blob/main/CMakeLists.txt)
 > file has options for configuring which parts of the project to enable.<br>
 > &nbsp;&nbsp;&nbsp;&nbsp;These are further documented in [CMake Options and Variables](cmake_options_and_variables.md).
 
@@ -97,7 +97,7 @@
 ```
 
 Translate a
-[MLIR file](https://github.com/google/iree/blob/master/iree/tools/test/simple.mlir)
+[MLIR file](https://github.com/google/iree/blob/main/iree/tools/test/simple.mlir)
 and execute a function in the compiled module:
 
 ```powershell

diff --git a/docs/GetStarted/getting_started_windows_vulkan.md b/docs/GetStarted/getting_started_windows_vulkan.md
index 9ceee2a..4e6c7b9 100644
--- a/docs/GetStarted/getting_started_windows_vulkan.md
+++ b/docs/GetStarted/getting_started_windows_vulkan.md

@@ -39,7 +39,7 @@
 ### Quick Start
 
 The
-[dynamic_symbols_test](https://github.com/google/iree/blob/master/iree/hal/vulkan/dynamic_symbols_test.cc)
+[dynamic_symbols_test](https://github.com/google/iree/blob/main/iree/hal/vulkan/dynamic_symbols_test.cc)
 checks if the Vulkan loader and a valid ICD are accessible.
 
 Run the test:
@@ -58,7 +58,7 @@
 HAL, which includes checking for supported layers and extensions.
 
 Run the
-[device creation test](https://github.com/google/iree/blob/master/iree/hal/cts/device_creation_test.cc):
+[device creation test](https://github.com/google/iree/blob/main/iree/hal/cts/device_creation_test.cc):
 
 ```powershell
 # -- CMake --