fix: support `connection_pool` v3

[G-Rath]

Summary

connection_pool v3+ requires keyword arguments instead of positional args, but also drops support for Ruby 3.2 so this has us check the version being used and do the right thing accordingly

Other Information

Resolves #1366

Pull Request checklist

• [x] Add/update test to cover these changes
• [x] ~Update documentation~
• [x] Update CHANGELOG file

[mhfs]

Thanks @G-Rath. Came here for the same issue and was happy to see your PR.

[izn]

Any updates on when this can be merged?

[kapso]

thanks @G-Rath

@justin808 any plans for doing a release? thanks