REDbot's versioning scheme

[mnot]

I recently changed to calver, because REDbot is a service that doesn't really get used as a library, and because the currency of the checks that it implements is relevant to its users.

However, we're also moving most of those checks to httplint (see #330), so it's likely that in the future, the date of the last release isn't necessarily as good an indicator as to how up-to-date it is; the underlying changes in httplint are what are more likely to matter.

httplint is calendar versioned, so I'm thinking of moving redbot back to semantic versioning (deleting the calendar-based versions on pypi and GitHub). That would allow us to have a UX that indicates version something like this:

Redbot 2.0.1 (httplint 2023.11.2)

I think I like the properties of that.

The only wrinkle here is that now that calendar versioned REDbot has been released, we'd be "rolling back the clock" to get it back to version 2, and any installations of the recenct calver versions will have to be force-reinstalled.

I think that's OK, because a) redbot is not a library, and b) I don't think it should affect many. I'd put a clear warning in README and let it sit out there for a few months to guide people as to how to handle it.

Any reactions?