Add github workflow for auto PR labeling (#179)

Co-authored-by: Harshit Mehta <harshitm@nvidia.com>

.github/workflows/pull-request-labeler.yaml

@@ -0,0 +1,14 @@
+name: "Pull Request Labeler"
+on:
+- pull_request_target
+
+jobs:
+  triage:
+    permissions:
+      contents: read
+      pull-requests: write
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/labeler@v4
+      with:
+        repo-token: "${{ secrets.GITHUB_TOKEN }}"