Add a first Github Action for JUnit

.github/workflows/ci.yml

@@ -0,0 +1,23 @@
+name: tests
+on: push
+jobs:
+  run_tests:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout the repository
+        uses: actions/checkout@v2
+
+      - name: Set up JDK 8
+        uses: actions/setup-java@v1
+        with:
+          java-version: 8
+
+      - name: Cache Maven packages
+        uses: actions/cache@v2
+        with:
+          path: ~/.m2
+          key: ${{ runner.os }}-m2-${{ hashFiles('**/pom.xml') }}
+          restore-keys: ${{ runner.os }}-m2
+
+      - name: Run tests with Maven
+        run: mvn -B test --file pom.xml