ci: Update GitHub Actions permissions

Author: holtskinner

.github/workflows/update-a2a-types.yml

@@ -8,6 +8,8 @@ on:
 jobs:
   check_and_update:
     runs-on: ubuntu-latest
+    permissions:
+      contents: write
 
     steps:
       - name: Checkout code
@@ -59,7 +61,7 @@ jobs:
           echo "Codegen finished."
 
       - name: Commit and push if generated file changed
-        if: github.ref == 'refs/heads/main' # Or your default branch name
+        if: github.ref == 'refs/heads/main'
         run: |
           set -euo pipefail