Remove castore dependency

[wojtekmach]

Closes #178.

Mint was recently updated to automatically use OS trust store: elixir-mint/mint#435.

If we are on OTP 24, we'd receive this error:

Same error when using OTP 25+ but the OS happens not to have certs:

I believe the error is good enough however I'm happy to improve it of course!

[sneako]

Thanks @wojtekmach !

[wojtekmach]

@sneako actually let's hold off on this for a second, perhaps we should set Mint version requirement to >= 1.6.1 so we always pick a Mint which would use OS certs?

[PragTob]

Less dependencies is always great 👀

Any way to help this move along? Looks like one failing test 👀

[wojtekmach]

The failing line is this one:

finch/test/finch/http2/pool_test.exs

Line 239 in 047a417

assert_recv_frames([rst_stream(stream_id: ^stream_id, error_code: :no_error)])

I have determined it started failing after this Mint change, elixir-mint/mint#434, which makes sense, Mint stopped sending frames under some circumstances and the test is expecting these. Perhaps it's as simple as updating the test?

cc @v0idpwn

[wojtekmach]

Mint is using OS trust store since 1.6.1. I thought I'd require the latest available version at the moment, 1.6.2: https://github.com/elixir-mint/mint/blob/main/CHANGELOG.md#v162.

[sneako]

❤️