Make it compatible with Rails 7.2

[edmartins]

PgpoolNoLoadBalance::PostgreSQLAdapterMissing: No postgresql adapter specified by 'config/database.yml', or 'ActiveRecord::Base.establish_connection' method is not called. (PgpoolNoLoadBalance::PostgreSQLAdapterMissing)

[elengine]

Hi @edmartins,

First of all, thank you so much for your previous pull request for Rails 7.1! I've just merged it, and I really appreciate your help in keeping this library up-to-date.

It's fantastic to see you've already followed up with this PR for Rails 7.2 support. Thank you for your continued effort!

Before I can review this one, could you please take care of a couple of things?

1. It looks like this branch now has a merge conflict, most likely because the Rails 7.1 PR was just merged. Could you please rebase your branch onto the latest master to resolve it?
2. Just as a quick check to prevent any regressions, could you also confirm that these changes for 7.2 still work perfectly with Rails 7.1?

Looking forward to getting this merged as well. Thanks again for your great contributions!