Add support for 'docker version' and 'podman version'

[LewisGaul]

Fixes #591

• Resolve what to do about the added requirement for pydantic v2
  • Making it work with pydantic v1 for now (although podman's APIVersion and BuiltTime fields won't be recognised with pydantic v1)
  • Raised separate issue for removing pydantic v1 support: Drop support for pydantic v1 #594
• Add tests

[gabrieldemarmiesse]

I would be happy to drop support for pydantic V1 when it's end of life, so in one month. If this PR is not a pressing matter, we can merge it just after :)

[LewisGaul]

This makes just pytest work from the project root, rather than needing python3 -m pytest

[gabrieldemarmiesse]

Looks good as usual! We can merge when pydantic v1 is EOL

[LewisGaul]

Looks good as usual! We can merge when pydantic v1 is EOL

To be clear, I updated it to be compatible with pydantic v1 so that we don't need to wait.

[gabrieldemarmiesse]

Ho my bad, I went over it a bit too quickly since I already read the diff once. Let's merge it now :)