ci: standardize release branch pattern to release-X.Y.x (#3999)

Standardize CI workflows to use `release-X.Y.x` branch pattern instead
of multiple numeric variants.

That's the pattern we are settling on. See
https://github.com/llamastack/llama-stack-ops/pull/20 for reference.

.github/workflows/pre-commit.yml

@@ -7,9 +7,7 @@ on:
   push:
     branches:
       - main
-      - 'release-[0-9]+.[0-9]+.[0-9]+.[0-9]+'
-      - 'release-[0-9]+.[0-9]+.[0-9]+'
-      - 'release-[0-9]+.[0-9]+'
+      - 'release-[0-9]+.[0-9]+.x'
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.ref == 'refs/heads/main' && github.run_id || github.ref }}