Bug fixes:
- Fix platform specific gems removed from the lockfile #6266
- Properly handle incompatibilities on platform specific gems #6270
- Optimistically exclude prereleases from initial resolution #6246
- Fix another case of not properly falling back to ruby variant when materializing #6261
- Skip setting
BUNDLER_SETUPon Ruby 2.6 #6252 - Let resolver deal with legacy gems with equivalent version and different dependencies #6219