ci: auto assign reviewer-team when open pr (#1274)

ci: auto assign reviewer-team when open issue/pr

Signed-off-by: bitliu <[email protected]>

.github/workflows/assignee.yaml

@@ -0,0 +1,19 @@
+name: Assign
+
+on:
+  pull_request_target:
+    types: [opened, reopened]
+
+jobs:
+  assign:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/github-script@v6
+        with:
+          script: |
+            github.rest.pulls.requested_reviewers({
+              pull_number: context.issue.number,
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              team_reviewers: ['envoyproxy/gateway-reviewers']
+            })