This `#use_puma?` check was [introduced][1] because Rails could
potentially display the wrong server URL in development if another host
or port is configured in `config/puma.rb`.

However, in Rack 3 the the name of the server class changed from
`Rack::Handler::Puma` to `Rackup::Handler::Puma`, which means that the
served_url is being logged again.

This commit fixes the check to accept either version of the class.
Additionally, puma was updated in Gemfile.lock because Puma 6.0.x prints
a deprecation warning about Rack::Handler that's fixed in 6.1.0.

[1]: 29648ff6