ci: Add a default GitHub workflow

.github/workflows/build.yml

@@ -0,0 +1,25 @@
+name: Build with Gradle
+
+on:
+  push:
+    branches: [ 'main' ]
+  pull_request:
+    branches: [ 'main' ]
+
+jobs:
+  build:
+    runs-on: ubuntu-22.04
+    permissions:
+      contents: read
+
+    steps:
+      - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
+      - name: Set up JDK
+        uses: actions/setup-java@9704b39bf258b59bc04b50fa2dd55e9ed76b47a8 # v4.1.0
+        with:
+          java-version-file: '.java-version'
+          distribution: 'temurin'
+      - name: Setup Gradle
+        uses: gradle/actions/setup-gradle@417ae3ccd767c252f5661f1ace9f835f9654f2b5 # v3.1.0
+      - name: Build with Gradle Wrapper
+        run: ./gradlew build

.java-version

@@ -0,0 +1 @@
+17