In the universal resolver, we prioritize solving for as few versions as possible. Sometimes, users instead want to get the newest possible version for every fork (e.g., they'd prefer getting the newest versions of foo for Python 3.10+, even if it means they have two versions of foo in the lockfile, one for Python 3.9 and earlier, and one for Python 3.10 and later).

(--universal-strategy is obviously a bad name.)

One implementation of this would be to ignore preferences from other forks.