Set up Actions PR pipeline (#18)

Create Actions PR pipeline - this will automatically run on opened Pull Requests to make sure they compile and pass all (future) tests.

.github/workflows/pr-pipeline.yml

@@ -0,0 +1,23 @@
+# This workflow will build a Java project with Maven
+# For more information see: https://help.github.com/actions/language-and-framework-guides/building-and-testing-java-with-maven
+
+name: PR-maven-package
+
+on:
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up JDK 8
+      uses: actions/setup-java@v2
+      with:
+        java-version: '8'
+        distribution: 'adopt'
+    - name: Build with Maven (compile -> test -> package)
+      run: mvn -B package --file pom.xml