Bump version to 3.2.0 after releasing 3.1.0. (#19638)

See https://github.com/iree-org/iree/issues/19192

compiler/version.json

diff --git a/compiler/version.json b/compiler/version.json
index 9519501..4d26484 100644
--- a/compiler/version.json
+++ b/compiler/version.json
@@ -1,3 +1,3 @@
 {
-  "package-version": "3.1.0.dev"
+  "package-version": "3.2.0.dev"
 }

runtime/version.json

diff --git a/runtime/version.json b/runtime/version.json
index 9519501..4d26484 100644
--- a/runtime/version.json
+++ b/runtime/version.json
@@ -1,3 +1,3 @@
 {
-  "package-version": "3.1.0.dev"
+  "package-version": "3.2.0.dev"
 }