Push the built but pre-test Docker image in parallel with the tests
run so that the image will be available for fetching from Docker Hub
if necessary, e.g. if you re-run the Codefresh run, or want to fetch
and debug a failing image locally.

This is mainly motivated by the fact that Codefresh no longer
provides its own repository for images, which it used to, and thus
no longer caches every built image including those that failed the
`run_tests` step.

These are the constraints for ixc-django-docker's dependencies that
worked for the RFDS site that uses Django 1.8, when re-creating that
project's pinned requirements.txt file from scratch.

DOTENV is useful in many places, such as setting unique names for
things like databases or ElasticSearch indexes etc.

Make it easily available as a setting that is guaranteed to be
present, and given a clear default value if not, instead of requiring
projects to hunt for and handle the 'DOTENV' environment variable.

…onment

* master:
  Do not match pyenv error string accidentally, which says the required version is NOT installed.
  Fix flipped bool test.
  Actually exit when dependencies are not met.
  Don't specify base image version in comments.
  Remove extra blank line.
  Export `CPATH` so zlib headers can be found from Xcode while building wheels in Catalina.

The `admin_tools` app comes from django-admin-tools which isn't
referenced anywhere else in ixc-django-docker, so this was probably
added to the default URLs by mistake.

For RFDS the site admin is under /rfds-admin/ not /admin/. The new
ADMIN_URL setting makes the admin URL prefix easily configurable in
downstream projects without needing to mess with URL patterns.

* master:
  Add missing `revision` to main clone step.

This step is redundant in setup.sh because it gets run as part of
the recommended Dockerfile when building an image. Before this change
static files etc would get generated by the Codefresh build, then
again slowly and pointlessly when you run the setup service.

So either this command should be removed altogether from this script,
or maybe be adjusted to run only in a local development context?