My application spends more than 30% of time during `bundle update` comparing versions due to versions being sorted inside next_package_to_try. This has been addressed in pub_grub by defining a strategy interface (a `#next_package_and_version` method) which allows consumers to have finer control over the heuristic to select the next package to try. This commit implements the new strategy interface to remove extraneous version sorting (previously in next_package_to_try) since only the final count of versions is used. Combined with a previous change to pub_grub (already applied to Bundler), this commit results in `bundle update` taking only half the time it did on 2.6.5. https://github.com/rubygems/rubygems/commit/62f69e27f0