Add GitHub Actions workflow

Author: SamJakob

.github/workflows/checks.yml

@@ -0,0 +1,49 @@
+name: Gradle Checks
+
+on:
+  push:
+    branches: [ "master" ]
+  pull_request:
+    branches: [ "master" ]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+
+    steps:
+      - uses: actions/checkout@v4
+      - name: Set up JDK 21
+        uses: actions/setup-java@v4
+        with:
+          java-version: '21'
+          distribution: 'temurin'
+
+      # Configure Gradle for optimal use in GitHub Actions, including caching of downloaded dependencies.
+      # See: https://github.com/gradle/actions/blob/main/setup-gradle/README.md
+      - name: Setup Gradle
+        uses: gradle/actions/setup-gradle@af1da67850ed9a4cedd57bfd976089dd991e2582 # v4.0.0
+
+      - name: Build with Gradle Wrapper
+        run: ./gradlew check
+
+  dependency-submission:
+
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+
+    steps:
+      - uses: actions/checkout@v4
+      - name: Set up JDK 21
+        uses: actions/setup-java@v4
+        with:
+          java-version: '21'
+          distribution: 'temurin'
+
+      # Generates and submits a dependency graph, enabling Dependabot Alerts for all project dependencies.
+      # See: https://github.com/gradle/actions/blob/main/dependency-submission/README.md
+      - name: Generate and submit dependency graph
+        uses: gradle/actions/dependency-submission@af1da67850ed9a4cedd57bfd976089dd991e2582 # v4.0.0

demo/build.gradle.kts

@@ -27,7 +27,7 @@ java {
     targetCompatibility = JavaVersion.VERSION_21
 
     toolchain {
-        languageVersion = JavaLanguageVersion.of(23)
+        languageVersion = JavaLanguageVersion.of(21)
     }
 }