Add maven workflow action

Author: camporter

.github/workflows/maven.yml

@@ -0,0 +1,20 @@
+name: Java CI
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        java: [8, 11, 15]
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up JDK
+      uses: actions/setup-java@v1
+      with:
+        java-version: ${{matrix.java}}
+    - name: Build with Maven
+      run: mvn -B package --file pom.xml