Use PR docker image

Author: acogoluegnes

.github/workflows/test-pr.yml

@@ -24,6 +24,8 @@ jobs:
           cache: 'maven'
       - name: Start broker
         run: ci/start-broker.sh
+        env:
+          RABBITMQ_IMAGE: pivotalrabbitmq/rabbitmq:pr-13672-otp27
       - name: Test (no dynamic-batch publishing)
         run: |
           ./mvnw verify -Drabbitmqctl.bin=DOCKER:rabbitmq \