Github actions workflows fail on docker container pull

[duttonw]

Starting solr service container
  /usr/bin/docker pull ckan/ckan-solr-dev:2.9
  Error response from daemon: pull access denied for ckan/ckan-solr-dev, repository does not exist or may require 'docker login': denied: requested access to the resource is denied
  Warning: Docker pull failed with exit code 1, back off 7.312 seconds before retry.
  /usr/bin/docker pull ckan/ckan-solr-dev:2.9
  Error response from daemon: pull access denied for ckan/ckan-solr-dev, repository does not exist or may require 'docker login': denied: requested access to the resource is denied
  Warning: Docker pull failed with exit code 1, back off 9.989 seconds before retry.
  /usr/bin/docker pull ckan/ckan-solr-dev:2.9
  Error response from daemon: pull access denied for ckan/ckan-solr-dev, repository does not exist or may require 'docker login': denied: requested access to the resource is denied
  Error: Docker pull failed with exit code 1