Update pr.yml to fix permission issues in alpha release

Author: dotansimha

.github/workflows/pr.yml

@@ -14,6 +14,7 @@ jobs:
     permissions:
       contents: read
       id-token: write
+      pull-requests: write
     uses: the-guild-org/shared-config/.github/workflows/release-snapshot.yml@v1
     if: ${{ github.event.pull_request.title != 'Upcoming Release Changes' }}
     with: