Add build workflow.

Author: dkocher

.github/workflows/build.yml

@@ -0,0 +1,23 @@
+name: Build
+
+on:
+  push:
+  pull_request:
+    branches:
+      - master
+jobs:
+  build:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ ubuntu-latest ]
+    steps:
+      - uses: actions/checkout@v4
+      - name: Set up JDK
+        uses: actions/setup-java@v4
+        with:
+          distribution: 'temurin'
+          java-version: 21
+          cache: maven
+      - name: Build with Maven
+        run: mvn --no-transfer-progress --batch-mode verify