Upgrade GitHub Actions to v4

.github/workflows/check.yml

@@ -0,0 +1,31 @@
+name: Check
+on: [ pull_request, push ]
+jobs:
+  check:
+    runs-on: ubuntu-latest
+    # push: always run.
+    # pull_request: run only when the PR is submitted from a forked repository, not within this repository.
+    if: github.event_name == 'push' || github.event.pull_request.head.repo.full_name != github.repository
+    strategy:
+      fail-fast: false
+    steps:
+    - uses: actions/checkout@v4
+    - name: Set up OpenJDK 8
+      uses: actions/setup-java@v4
+      with:
+        java-version: 8
+        distribution: "temurin"
+        cache: "gradle"
+    - name: Check
+      run: ./gradlew --info --stacktrace test
+    - uses: actions/upload-artifact@v4
+      if: always()
+      with:
+        name: tests
+        path: ./build/reports/tests/test
+    - name: Generate JaCoCo test report
+      run: ./gradlew jacocoTestReport coveralls
+    - uses: actions/upload-artifact@v4
+      with:
+        name: jacoco
+        path: ./build/reports/jacoco/test