Feature: Versioning Scheme

[seangwright]

Is your feature request related to a problem? Please describe.
Developers can't tell when parts of the style guide have been updated.
There's also no explanation of how it changes with updates to Xperience.

Describe the solution you'd like
We should come up with a versioning scheme for the style guide as a whole that is showing in the GitHub Releases for the repo.

We should also figure out how to indicate which recommendations might be version specific (ex: "Requires Hotfix 5").

Describe alternatives you've considered
We should definitely version the guide, but as for version-specific recommendations we could indicate that all recommendations are for the latest version of Xperience.