ci: added workflow to automatically add reviewers to pull requests

.github/workflows/pr-setup.yml

@@ -0,0 +1,20 @@
+name: Pull request setup
+on:
+  pull_request:
+    types:
+      - opened
+      - ready_for_review
+
+permissions:
+  contents: read
+  pull-requests: write
+
+jobs:
+  add-reviewers-assignees:
+    name: Add reviewers and assignees
+    runs-on: ubuntu-latest
+    steps:
+      - name: Add reviewers and assignees
+        uses: kentaro-m/auto-assign-action@v2.0.0
+        with:
+          configuration-path: .github/auto_assign.yml