add github actions for ci.

.github/mergify.yml

@@ -0,0 +1,8 @@
+pull_request_rules:
+  - name: Automatic merge on approval
+    conditions:
+      - check-success=WIP
+      - check-success=restyled
+    actions:
+      merge:
+        method: merge

.github/workflows/gradle.yml

@@ -0,0 +1,20 @@
+name: Publish plugin
+on:
+  push:
+    branches: [ master ]
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: Set up JDK 17
+        uses: actions/setup-java@v3
+        with:
+          java-version: '17'
+          distribution: 'adopt'
+      - name: Grant execute permission for gradlew
+        run: chmod +x gradlew
+      - name: Build with Gradle
+        run: ./gradlew publishPlugin
+        env:
+          PUBLISH_TOKEN: ${{ secrets.PUBLISH_TOKEN }}