Lacks support for ConnectionPool 3

[PikachuEXE]

https://github.com/mperham/connection_pool/blob/main/Changes.md#300

3.0.0 BREAKING CHANGES ConnectionPool and ConnectionPool::TimedStack now use keyword arguments rather than positional arguments everywhere. Expected impact is minimal as most people use the with API, which is unchanged.
Dropped support for Ruby <3.2.0

Ruby support requirements tie in with drbrain/net-http-persistent#160

Above copied from drbrain/net-http-persistent#162

That project got an open PR already: drbrain/net-http-persistent#163

[benubois]

Thanks for pointing this out. Feel like submitting a PR?

[PikachuEXE]

#138