Add label checking for group reviews (#153)

* Feat: Add ability to check for a label marking a group review approval

* Docs(ci): Add documentation about group review label

* Docs(ci): Add example of GitHub CLI adding a label to a pr

.github/workflows/check_review_label.yaml

@@ -0,0 +1,20 @@
+name: Verify group review
+
+on:
+  pull_request:
+    types:
+      - opened
+      - labeled
+
+env:
+  TARGET_LABEL: 'group_review_lgtm'
+
+jobs:
+  check_review_label:
+    runs-on: ubuntu-latest
+    steps:
+      - run: echo "::error Missing review label" && exit 1
+        if: "!contains(github.event.pull_request.labels.*.name, env.TARGET_LABEL)"
+
+      - run: echo "Has review label"
+

ci/README.md

@@ -1,5 +1,12 @@
 # Workflows in this repository
 
+## Verify group review
+This workflow requires PRs to have an additional label before they can be merged into the main branch.  Currently the label is `group_review_lgtm`, which is intended to be issued once the PR has been through a group review.
+
+This can be done via the GitHub CLI by using the command
+`gh pr edit <PR NUMBER> --add-label group_review_lgtm`.
+
+
 ## Verify PR has JIRA ticket and issue number
 This workflow is designed to enforce requirements for PR descriptions.  At bare minimum it requires the PR to mention a related issue and mention the Jira Ticket number.  Both of these are required since Sync2Jira does not know how to associate a PR with a Jira Ticket from the originating GitHub issue.