[Fix] Infra: grant contents:write to create-release-branch caller job

The create-branch job in create-release.yml calls the reusable
create-release-branch.yml workflow, which requires contents: write.
The top-level permissions: {} blocks the inherited default, and only
the release job overrode it, so the nested call failed with:

  The nested job 'create-branch' is requesting 'contents: write',
  but is only allowed 'contents: none'.

Add the permission at the calling job level so the reusable
workflow is granted what it needs.

.github/workflows/create-release.yml

@@ -110,6 +110,8 @@ jobs:
   create-branch:
     name: Create Release Branch
     needs: release
+    permissions:
+      contents: write
     uses: ./.github/workflows/create-release-branch.yml
     with:
       tag: ${{ inputs.tag }}