Fix condition for event name in auto-assign workflow

Author: wachawo

.github/workflows/auto-assign.yml

@@ -12,7 +12,7 @@ jobs:
       pull-requests: write
     steps:
       - name: Auto-assign and request reviewers
-        if:  github.event_name == 'issue' || github.event_name == 'pull_request'
+        if:  github.event_name == 'issues' || github.event_name == 'pull_request'
         uses: wachawo/github-auto-assign@v1
         with:
           repo-token: ${{ secrets.GITHUB_TOKEN }}