message: Update images/rabbitmq/Dockerfile to reflect 3.11 dependency
diff: ARG IMAGE_REPO
  FROM ${IMAGE_REPO:-lagoon}/commons as commons
  -# alpine 3.10 as per https://github.com/docker-library/rabbitmq/blob/master/3.8/alpine/Dockerfile
  +# alpine 3.11 as per https://github.com/docker-library/rabbitmq/blob/master/3.8/alpine/Dockerfile
  FROM rabbitmq:3.8-management-alpine
  ARG LAGOON_VERSION
  