Fix labels API endpoint (#3430)

Of course you must read labels from issues not pulls endpoint

Author: gatesn

.github/workflows/labels.yml

@@ -15,7 +15,7 @@ jobs:
         id: get_labels_api
         uses: octokit/[email protected] # Use an action to make API requests
         with:
-          route: GET /repos/{owner}/{repo}/pulls/{pull_number}/labels
+          route: GET /repos/{owner}/{repo}/issues/{pull_number}/labels
           owner: ${{ github.repository_owner }}
           repo: ${{ github.event.repository.name }}
           pull_number: ${{ github.event.pull_request.number }}