build: add build & release-please workflow

.github/workflows/main.yml

@@ -0,0 +1,36 @@
+name: main
+
+on: [pull_request, push]
+
+jobs:
+  build:
+    strategy:
+      matrix:
+        java: [ 21 ]
+    runs-on: ubuntu-latest
+    steps:
+      - name: checkout repository
+        uses: actions/checkout@v4
+      - name: validate gradle wrapper
+        uses: gradle/wrapper-validation-action@v2
+      - name: setup jdk ${{ matrix.java }}
+        uses: actions/setup-java@v4
+        with:
+          java-version: ${{ matrix.java }}
+          distribution: 'microsoft'
+      - name: setup gradle
+        uses: gradle/actions/setup-gradle@v3
+      - name: execute gradle build
+        run: ./gradlew build
+
+  release-please:
+    needs: [ build ]
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+      pull-requests: write
+    steps:
+      - uses: google-github-actions/release-please-action@v4
+        with:
+          token: ${{ secrets.RELEASE_PLEASE_TOKEN }}
+          release-type: java-yoshi