chore: add write permissions to generate new client job (#11498)

Add `contents: write` and `pull-requests: write` permissions to the new client generation workflow.

This is necessary due to the default workflow permissions being read-only now.

Author: meltsufin

.github/workflows/generate_new_client_hermetic_build.yaml

@@ -52,6 +52,9 @@ on:
 jobs:
   generate:
     runs-on: ubuntu-22.04
+    permissions:
+      contents: write
+      pull-requests: write    
     steps:
       - uses: actions/checkout@v4
       - uses: actions/setup-python@v4