Release branch settings (#314)

* track changes to repo protection for release branches

* add required-status-check to build

* Update .github/workflows/build.yaml

.github/repository-settings.md

@@ -11,7 +11,14 @@ settings](https://github.com/open-telemetry/community/blob/main/docs/how-to-conf
 - Require branches to be up to date before merging: UNCHECKED
   (PR jobs take too long, and leaving this unchecked has not been a significant problem)
 
+### `release/*`
 
+Same settings as above for `main`, except:
+
+* Restrict pushes that create matching branches: UNCHECKED
+
+  (So that opentelemetrybot can create release branches)
+
 ## Secrets and variables > Actions
 
 * `GPG_PASSWORD` - stored in OpenTelemetry-Java 1Password

.github/workflows/build.yaml

@@ -39,4 +39,14 @@ jobs:
     if: failure() && github.run_attempt == 1
     uses: ./.github/workflows/reusable-workflow-notification.yml
     with:
-      success: ${{ needs.build.result == 'success' }}
+      success: ${{ needs.build.result == 'success' }}
+
+  required-status-check:
+    needs:
+      - build
+    runs-on: ubuntu-latest
+    if: always()
+    steps:
+      - if: |
+          needs.build.result != 'success'
+        run: exit 1