Add support for connection_pool >= 3.0

[jukra]

• Added support for connection_pool >= 3.0 (Lacks support for ConnectionPool >= 3.0 #162) by adapting to ConnectionPool 3.x's keyword argument requirements. Pool#initialize was simplified to use **options syntax (compatible with both versions), while TimedStackMulti#initialize uses conditional logic based on ConnectionPool version due to different subclass super() behavior.
• Fixed confusing test syntax that relied on Ruby's keyword-to-hash conversion behavior. For example here, I think we were actually using { connection_args: popped } as the obj (https://github.com/mperham/connection_pool/blob/v2.5.5/lib/connection_pool/timed_stack.rb#L38) ?

stack.push connection_args: popped

So I added the connection_args with another value for clear separation of obj and options (https://github.com/mperham/connection_pool/blob/v3.0.2/lib/connection_pool/timed_stack.rb#L38)

stack.push popped, connection_args: 'default'

to make the tests more clear.

[mscrivo]

Should someone be tagged to take a look at this? Probably blocking a lot of folks from upgrading sidekiq

[jukra]

@tenderlove when you have a second, could you take a look at this?

[tenderlove]

Ooof. Thanks for being persistent (lol). It looks good, I'll merge and release after CI returns.

[PikachuEXE]

I think we should also update ubuntu version since 20.04 is removed
https://github.blog/changelog/2025-02-12-notice-of-upcoming-deprecations-and-breaking-changes-for-github-actions/

[tenderlove]

I think we should also update ubuntu version since 20.04 is removed

I sent a PR to modernize CI. Unfortunately it seems like we have some legit failures on modern Ruby #165

I'll try to get it fixed and then ship all of these.

[tenderlove]

This should be shipped now as v4.0.7. I've also switched the release process to use trusted publishing. If there's any problems, please let me know and I'll ship a new version!

[slbug]

@tenderlove thank you, works as expected