Add GH workflow; JDK 11 (#14)

Author: adamdickmeiss

.github/workflows/mvn-verify.yaml

@@ -0,0 +1,16 @@
+name: mvn-verify
+on: [push, pull_request]
+
+jobs:
+  mvn-verify:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+    - name: Set up JDK 11
+      uses: actions/setup-java@v4
+      with:
+        java-version: '11'
+        distribution: 'temurin'
+        cache: maven
+    - name: Run the Maven verify phase
+      run: mvn --batch-mode verify