Add workflow to build spring batch extensions

.github/workflows/extension-build.yml

@@ -0,0 +1,39 @@
+name: Spring Batch Extension Build
+
+on:
+  workflow_dispatch:
+    inputs:
+      extension:
+        description: "Extension name"
+        required: true
+        type: choice
+        options:
+          - spring-batch-bigquery
+          - spring-batch-excel
+          - spring-batch-elasticsearch
+          - spring-batch-geode
+          - spring-batch-neo4j
+
+jobs:
+  build:
+    name: Build an extension
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout source code
+        uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
+        with:
+          name: spring-projects/spring-batch-extensions
+          ref: 'main'
+
+      - name: Set up JDK 17
+        uses: actions/setup-java@387ac29b308b003ca37ba93a6cab5eb57c8f5f93 # v4.0.0
+        with:
+          java-version: '17'
+          distribution: 'temurin'
+
+      - name: Capture extension name
+        run: echo EXTENSION_NAME=${{ github.event.inputs.extension }} >> $GITHUB_ENV
+
+      - name: Build extension with Maven
+        run: mvn -B package --file pom.xml
+        working-directory: ${EXTENSION_NAME}