Bump cmake to 3.16.3. (#7180)
* The thing that tipped it was lack of NumPy configuration in 3.13.
* Picked 3.16.3 because it is deployed with Ubuntu 20.04LTS, which at least gives it a pretty big fanout with respect to use (more as a "hey, this gets used a lot and may be ok" vs "we need to pin to Ubuntu").
diff --git a/build_tools/docker/cmake-python-vulkan/Dockerfile b/build_tools/docker/cmake-python-vulkan/Dockerfile
index cdaea33..954cf76 100644
--- a/build_tools/docker/cmake-python-vulkan/Dockerfile
+++ b/build_tools/docker/cmake-python-vulkan/Dockerfile
@@ -8,7 +8,7 @@
# This image provides the Vulkan SDK. Requires a child image to provide
# a Vulkan ICD.
-FROM gcr.io/iree-oss/cmake-python@sha256:055eba8441ada5e0241f102241747e8d61196dca7f04316a0bfd68d2769883dc AS final
+FROM gcr.io/iree-oss/cmake-python@sha256:7e31103ee35f52e6d6019adf474bc60758710e95f20ee33ed94aee3f8780edbd AS final
ARG VULKAN_SDK_VERSION=1.2.154.0
