add github actions

.github/workflows/maven.yml

@@ -0,0 +1,20 @@
+name: Java CI
+
+on: [push]
+
+jobs:
+  build:
+    strategy:
+      matrix:
+        java: [ 8, 9, 11, 15 ]
+    runs-on: ubuntu-latest
+    name: Java ${{ matrix.java }} compile
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up JDK ${{ matrix.java }}
+      uses: actions/setup-java@v1
+      with:
+        java-version: ${{ matrix.java }}
+    - name: Build with Maven
+      run: mvn -fae -U -B clean license:check install -P check --file pom.xml