anchor.diff: -FROM postgres:11-alpine
  +FROM postgres:11.3-alpine
   
   ### Versions
  -ARG CGAL_VERSION="4.13"
  +ARG CGAL_VERSION="4.13.1"
   ARG SFCGAL_VERSION="1.3.6"
  -ARG POSTGIS_VERSION="2.5.1"
  +ARG POSTGIS_VERSION="2.5.2"
   
   ### Download Locations
   ARG CGAL_SOURCE="https://github.com/CGAL/cgal/releases/download/releases%2FCGAL-$CGAL_VERSION/CGAL-$CGAL_VERSION.tar.xz"
  
positive.code: ARG POSTGIS_SOURCE="https://download.osgeo.org/postgis/source/postgis-$POSTGIS_VERSION.tar.gz"
  
  ### Checksums
  ARG CGAL_SHA256="3e3dd7a64febda58be54c3cbeba329ab6a73b72d4d7647ba4931ecd1fad0e3bc"
  #ARG POSTGIS_SHA256="b9754c7b9cbc30190177ec34b570717b2b9b88ed271d18e3af68eca3632d1d95"
  
  ### update apk and existing packages
  
negative.code:     ### build packages from testing repo
      && apk add --virtual .build-deps-testing \
          --repository http://dl-cdn.alpinelinux.org/alpine/edge/testing \
          geos-dev \
          protobuf-c-dev \
      ### various runtime packages 
      && apk add --virtual .postgis-run-deps-edge \
  