Update versioning scheme

[thekaveman]

After some discussion with the team, we've decided to drop v prefixes from version numbers. Among many reasons, this will allow us to more easily auto-increment the version number via GitHub Actions workflows on certain events.

Since we've only released v0.0.1 here, it's a good time to make the version change.

As for scheme, the two main choices are traditional semver MAJOR.MINOR.PATCH or newer calver YEAR.MONTH.RELEASE where RELEASE is the Nth release that month. The choice here should align with cal-itp/benefits#180

[thekaveman]

Since we decided on Calver for cal-itp/benefits#180, we'll use that here too. The next release will be version 2022.01.1