[emails] Breachchecker.com url dead

[ximad]

Breachchecker.com history of data leaks associated with a particular email address seems parked

[Coordinate-Cat]

Regardless of this URL, it might be better to use GitHub Actions in this repository.
It looks like this repository hasn't been updated for a while...

https://github.com/marketplace/actions/markdown-link-check

@cipher387