Pass filename to `--read-from-stdin` option to fix `credo` inconsistency

[GiovanniHessel94]

Hello guys!

I've found an inconsistency when running mix credo with the --read-from-stdin option that seems to be used by this extension, and it looks that we have to pass the filename together with it to fix that, as pointed out in this comment.

If you guys agree, I think I can do it myself as it seems quite simple.

[ulfurinn]

The effects of this seem to have become worse under credo 1.7.4, Credo.Check.Warning.WrongTestFileExtension is now firing on every file.

[pantajoe]

Thanks for raising the issue! Apologies for the delay, life's been busy lately 😬 But I'm planning to come back and do a rewrite and fix a lot of the raised bugs in the next weeks. If you want, @GiovanniHessel94, go ahead in drafting in PR, so we can fix this error which I imagine to be quite annoying 😅