[RFC] Move to month-based (semantic) versioning

There have been various discussions historically about rethinking our versioning

Essentially - as we are unlikely to ever create a 2.x.x version - the preceding "1." is superfluous

The 2 proposals that have been considered:

- bump minor -> major - so eg next version would 31.0 rather than 1.31.0
- use date-based versions - so on the basis that the next release happens in 2024/04, the next version would be 202404.0

personally, im not opposed to date-based versions (**as long as they are semantic**)

a concern is that version is not strictly associated to the date - so patch releases in this schema would be 202404.x, but might be actually released a year later

if we make any change to this it will require quite a bit of work to update/fix release tooling - not a huge amount, but significant

i think the main advantage of date-based versions is that they carry more information, with possible downside of being misleading for later patches