E-mail validation doesn't accept addresses with unicode (RFC 6531)

[danschultzer]

Unicode e-mail addresses such as 你好@example.com and test@莎士比亚.org are valid, but due to the e-mail validation only being RFC 5332 compliant they can't be used with the default Pow.Ecto changeset.

Making the validation RFC 6531 compliant would solve this, but I'm pretty sure that RegExp can't be used for it. There was an issue on the W3C HTML5 specs where they went into the specifics. Also, it seems like several browsers still don't support the standard.

I'll check how other large OSS projects handles this, and figure out what would be the most straight forward approach to solve this.

Edit: The isemail npm package had a PR back in 2017 for this.