Revert "chore(deps): update actions/labeler action to v5" (finos#870)

Author: grahampacker-ms

.github/workflows/pr-labelling.yml

@@ -13,6 +13,6 @@ jobs:
       uses: actions/checkout@v4
 
     - name: Label PR based on changes
-      uses: actions/labeler@v5
+      uses: actions/labeler@v4
       with:
         repo-token: "${{ secrets.GITHUB_TOKEN }}"