anchor.diff:  
   
   # Declare common ruby base image for all ruby-stages
  -FROM ruby:2.6.2-alpine3.9 as gollum-ruby
  +FROM ruby:2.6.3-alpine3.10 as gollum-ruby
   
   
   FROM gollum-ruby as gollum-build
   
  +# See e.g. https://pkgs.alpinelinux.org/packages?name=icu-dev&branch=v3.10
   ARG ALPINE_SDK_VERSION=1.0-r0
  -ARG ICU_DEV_VERSION=62.1-r0
  +ARG ICU_DEV_VERSION=64.2-r0
   ARG GOLLUM_VERSION=4.1.4
   
   COPY --from=caddybuild --chown=1000:1000 /dist /dist
  
positive.code: # Build caddy from source, because binaries are published under a commercial license: https://caddyserver.com/pricing
  # Starting with 1.0.0 we seem to no longer have to do this:  https://github.com/mholt/caddy/releases/tag/v1.0.0
  # OTOH - with explicit plugin versions the build remains more deterministic than downloading the "latest" plugins via https://caddyserver.com/download
  FROM golang:1.12.4 as caddybuild
  
  # https://github.com/mholt/caddy/releases
  ARG CADDY_VERSION="v1.0.3"
  
negative.code:   # Needed for running gollum
    && apk --update add git=$GIT_VERSION \
    # Needed for setcap
    libcap=$LIBCAP_VERSION \
    # cleanup apk cache
    && rm -rf /var/cache/apk/* \
    # Initialize wiki data.
  