Auto label PRs with the ray-api label (#845)

* Add small workflow to auto-label all pr's targeting main with the ray-api label

Signed-off-by: Ayush Dattagupta <ayushdg95@gmail.com>

* Fix newline

Signed-off-by: Ayush Dattagupta <ayushdg95@gmail.com>

---------

Signed-off-by: Ayush Dattagupta <ayushdg95@gmail.com>

Author: ayushdg

.github/workflows/auto-labler.yml

@@ -0,0 +1,18 @@
+name: Label PRs to main
+
+on:
+  pull_request:
+    branches: [main]              # base branch filter
+
+permissions:
+  pull-requests: write            # needed to add labels
+
+jobs:
+  add-ray-api-label:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Add ray-api label
+        uses: actions-ecosystem/action-add-labels@v1
+        with:
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          labels: ray-api