message: Update images/postgres/Dockerfile to reflect 3.11 dependency
diff: ARG IMAGE_REPO
  FROM ${IMAGE_REPO:-lagoon}/commons as commons
  -# alpine 3.10 from https://github.com/docker-library/postgres/blob/master/11/alpine/Dockerfile
  +# alpine 3.11 from https://github.com/docker-library/postgres/blob/master/11/alpine/Dockerfile
  FROM postgres:11.6-alpine
  ARG LAGOON_VERSION
  