GH-138 - Set up integration builds against upcoming Spring Boot snapshots and milestones

Set up dedicated GitHub actions workflow to run tests against upcoming Spring Boot snapshots and milestones. Introduced with-preview-repos build profile to activate the Maven repositories containing snapshots and milestones.

.github/workflows/integration.yaml

@@ -0,0 +1,28 @@
+name: Compatibility Build
+
+on:
+  schedule:
+    - cron: '5 6 * * *'
+
+jobs:
+  integration:
+    strategy:
+      matrix:
+        profile: ['3.0.4-SNAPSHOT', '3.1.0-SNAPSHOT']
+    name: Build against Boot ${{ matrix.profile }}
+    runs-on: ubuntu-latest
+
+    steps:
+
+    - name: Check out sources
+      uses: actions/checkout@v3
+
+    - name: Set up JDK 17
+      uses: actions/setup-java@v3
+      with:
+        distribution: 'temurin'
+        java-version: 17
+        cache: 'maven'
+
+    - name: Build with Maven
+      run: ./mvnw -B -Pwith-preview-repos -Dspring-boot.version=${{ matrix.version }}

pom.xml

@@ -103,6 +103,28 @@ limitations under the License.
 
 		</profile>
 
+		<!-- For integration builds against milestones and snapshots -->
+
+		<profile>
+			<id>with-preview-repos</id>
+			<repositories>
+				<repository>
+					<id>spring-milestone</id>
+					<url>https://repo.spring.io/milestone</url>
+					<snapshots>
+						<enabled>false</enabled>
+					</snapshots>
+				</repository>
+				<repository>
+					<id>spring-snapshot</id>
+					<url>https://repo.spring.io/snapshot</url>
+					<releases>
+						<enabled>false</enabled>
+					</releases>
+				</repository>
+			</repositories>
+		</profile>
+
 		<profile>
 
 			<id>prepare-release</id>