Draft: build: integration test against `compatible_since` version

To give us the ability to have more confidence that the version noted in compatible_since is actually compatible with ??

This provides a helper method to allow us to quickly ??

Closes #538.

---

TODO:

• How do we handle newly added demos/features? Is that actually an issue or not?
  • It is - a new subcommand could be added and would fail to run on an older version
• Reference #533