github workflow (#16)

.github/workflows/maven.yml

@@ -0,0 +1,17 @@
+name: Java CI with Maven
+
+on: [push, pull_request]
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - uses: actions/setup-java@v1
+      with:
+        java-version: 11
+    - name: Build with Maven
+      run: mvn install
+    - uses: actions/upload-artifact@v2
+      with:
+        name: artifact
+        path: target