Use PR workflow

Author: ryanjbaxter

.github/workflows/maven.yml

@@ -0,0 +1,12 @@
+name: PR
+
+on:
+  pull_request:
+    branches: [ main, 4.3.x ]
+
+jobs:
+  build:
+    uses: spring-cloud/spring-cloud-github-actions/.github/workflows/pr.yml@main
+    with:
+      custom_build_command: |
+        ./mvnw clean install -B -U -Pspring,integration,docs