Add workflow to add PR labels

Author: Saransh-cpp

.github/labeler.yml

@@ -0,0 +1,2 @@
+needs release notes:
+- all: ['!docs/release.rst']

.github/workflows/needs_release_notes.yml

@@ -0,0 +1,13 @@
+name: "Pull Request Labeler"
+
+on:
+  - pull_request_target
+
+jobs:
+  triage:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/labeler@main
+      with:
+        repo-token: ${{ secrets.GITHUB_TOKEN }}
+        sync-labels: true