Give protobuf janitor access to edit prs/issues and exempt issues with the 'help wanted' tag.

The initial job ran and found stale PRs/issues, but lacked the permission to comment on them, add labels, or close issues/PRs.

Any issues with 'help wanted' shouldn't be auto-closed as we want them to be able to sit inactive.

PiperOrigin-RevId: 580209299

.github/workflows/janitor.yml

@@ -32,6 +32,9 @@ jobs:
   stale-others:
     name: Close stale non-copybara PRs and issues
     runs-on: ubuntu-latest
+    permissions:
+      issues: write # allow the action to comment on, add labels to, and close issues
+      pull-requests: write # allow the action to comment on, add labels to, and close PRs
     steps:
       - uses: actions/stale@b69b346013879cedbf50c69f572cd85439a41936
         with:
@@ -69,6 +72,7 @@ jobs:
             activity in the 14 days since the `inactive` label was added.
           stale-issue-label: 'inactive'
           stale-pr-label: 'inactive'
+          exempt-issue-labels: 'help wanted'
           days-before-stale: 90
           days-before-close: 14
           operations-per-run: 100