Add label workflow

.github/workflows/pull_request_label.yaml

@@ -0,0 +1,22 @@
+# This workflow applies labels to pull requests based on the paths that are
+# modified in the pull request.
+#
+# Edit `.github/labeler.yml` to configure labels. For more information, see
+# https://github.com/actions/labeler.
+
+name: Pull Request Labeler
+permissions: read-all
+
+on:
+  pull_request_target
+
+jobs:
+  label:
+    permissions:
+      pull-requests: write
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/labeler@8558fd74291d67161a8a78ce36a881fa63b766a9
+        with:
+          repo-token: "${{ secrets.GITHUB_TOKEN }}"
+          sync-labels: true