tox pulls docker image from local registry

[aryanagarwal9]

• Please check if the PR fulfills these requirements

• The commit message follows our guidelines
• Tests for the changes have been added (for bug fixes/features)
• Docs have been added / updated (for bug fixes / features)

• What kind of change does this PR introduce? (Bug fix, feature, docs update, ...)
  bug fix

• What is the current behavior? (You can also link to an open issue here)
  tox file builds the docker image itself

• What is the new behavior (if this is a feature change)?
  GitHub workflow builds the docker file, pushes it to the local registry, then that image is pulled by the tox file, and used to run the tests

• Does this PR introduce a breaking change? (What changes might users need to make in their application due to this PR?)
  No

• Other information:
  Please have a quick go through of the tox file to check if any more modifications are needed

[pandu-k]

Hi Aryan, thanks for this PR.

Can we make the pull-from-local registry tests be in addition to building and running the tests?

In some cases we will still want to run-and-build. For example, if we want to run this test suite directly on a remote machine.

I propose we create two sets of tests: one is build and test (the existing structure) and one pulls from the local registry (for use on GitHub CI).

By default, it should run build and test (via the tox command with no args). The tests that pull from the local registry should be specified to run (e.g: tox -e dind_os_local_registry)

[pandu-k]

Please update according to my comment