Add GitHub action workflow

.github/workflows/simplebuild.yml

@@ -0,0 +1,38 @@
+# https://docs.github.com/en/actions/using-workflows/workflow-syntax-for-github-actions
+name: OnPush
+on: [push, pull_request]
+env:
+  MAVEN_VERSION: 3.9.6
+jobs:
+  build_and_test:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Set up Java
+        uses: actions/setup-java@v4
+        with:
+          java-version: '17'
+          distribution: 'temurin'
+          architecture: x64
+
+      # Install Apache Maven >= 3.9; otherwise, we get the error,
+      #   "Detected Maven Version: 3.8.8 is not in the allowed range [3.9,)."
+      # Add Maven envars for subsequent actions:
+      #   * PATH: https://docs.github.com/en/actions/using-workflows/workflow-commands-for-github-actions#adding-a-system-path
+      #   * MAVEN_HOME: https://docs.github.com/en/actions/learn-github-actions/variables#passing-values-between-steps-and-jobs-in-a-workflow
+      - name: Install Apache Maven 3.9
+        run: |
+          sudo apt-get update && \
+            sudo apt-get install curl && \
+            curl -s -L https://dlcdn.apache.org/maven/maven-3/${MAVEN_VERSION}/binaries/apache-maven-${MAVEN_VERSION}-bin.tar.gz | tar xzf - -C /opt/ && \
+            echo "/opt/apache-maven-${MAVEN_VERSION}/bin/" >> $GITHUB_PATH && \
+            echo "MAVEN_HOME=/opt/apache-maven-${MAVEN_VERSION}/bin/" >> $GITHUB_ENV
+
+      - name: Compile and Package
+        # org.eclipse.mat.ui.rcp.tests fails without -Pskip-ui-tests
+        run: |
+          cd parent && \
+            mvn --version && \
+            mvn clean install -Pskip-ui-tests