Replace pytest-docker-compose with pytest-docker plugin

[BrianJKoopman]

Description

This does as the title says and replaces the use of the pytest plugin pytest-docker-compose with the plugin pytest-docker.

The difference is that pytest-docker-compose only supports docker-compose v1, while pytest-docker supports v2.

Motivation and Context

This, together with #482 fixes recent issues with installing socs.

#482 introduces a pin of pyyaml (pyyaml>6.0.1) which pytest-docker-compose (which pins to pyyaml<6) is incompatible with.

After seeing checks run, it turns out dropping this dependency completely fixes #478 without #482.

Fixes #478.

How Has This Been Tested?

I ran tests locally with this new plugin.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.