bumping triggers bundle which updates unrelated gem versions

[grosser]

given a gemspec project with Gemfile.lock including outdated versions, a bump minor updates the gems version in Gemfile.lock ... but it should only update the version of the gemspec gem ... I tried with --conservative flag, but that's not supported for a bundle or bundle install 🤷‍♂
so only workaround I can see if either setting some config flag or running bundle update <gem name> --conservative (might be tricky to find the name)
this seems to be triggered by the ruby version I'm on not matching the version it was last bundled with ... so this might be unfixable since it needs to bump to be able to bundle :(