Add merge queue rules (#37)

.github/workflows/merge-queue.yml

@@ -0,0 +1,15 @@
+name: Before Merge
+
+on:
+  merge_group:
+
+jobs:
+  validate-pr:
+    runs-on: ubuntu-latest
+    name: Build
+    steps:
+      - name: Setup Gradle
+        uses: gradle/actions/setup-gradle@af1da67850ed9a4cedd57bfd976089dd991e2582 # v4.0.0
+
+      - name: Clean Build with Gradle
+        run: ./gradlew clean build

.github/workflows/validate-pr.yml

@@ -0,0 +1,18 @@
+name: Validate PR
+
+# https://github.com/orgs/community/discussions/51120#discussioncomment-8623798
+on:
+  workflow_dispatch:
+  pull_request:
+
+jobs:
+  validate-pr:
+    if: ${{ github.event_name != 'pull_request' }} # see the link above
+    runs-on: ubuntu-latest
+    name: Build
+    steps:
+      - name: Setup Gradle
+        uses: gradle/actions/setup-gradle@af1da67850ed9a4cedd57bfd976089dd991e2582 # v4.0.0
+
+      - name: Clean Build with Gradle
+        run: ./gradlew clean build