Aassign contour-helm-chart-maintainers as reviewer for new PRs (#19)

Signed-off-by: Tero Saarni <[email protected]>

Author: tsaarni

.github/workflows/request-review.yaml

@@ -0,0 +1,18 @@
+on:
+  pull_request:
+    types: [opened, reopened, ready_for_review]
+
+permissions:
+  pull-requests: write
+
+jobs:
+  request-review:
+    if: github.repository == 'projectcontour/helm-charts'
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
+      - name: Request reviewers
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          gh pr edit ${{ github.event.pull_request.number }} --add-reviewer contour-helm-chart-maintainers