Ref T8116. A version has:
- a package (like "Arcanist") which it belongs to;
- a name (like "v3.1.5").
The name is immutable and unique, like the package key and publisher key.
Policy stuff:
- Versions have the exact same policies as their packages.
- You must be able to edit a package to create new versions of it.
This is still entirely uninteresting.
