Update permissions in the galata snapshot workflow (#7105)

Author: jtpio

.github/workflows/playwright-update.yml

@@ -12,7 +12,9 @@ jobs:
     if: ${{ github.event.issue.pull_request && contains(github.event.comment.body, 'update playwright snapshots') }}
     runs-on: ubuntu-latest
     permissions:
-      pull-requests: write # Required by actions/update-snapshots
+      # Required by actions/update-snapshots
+      contents: write
+      pull-requests: write
     strategy:
       fail-fast: false
       matrix: