Relax the RegEx restrictions to allow the new ICAAN TLDs.

New ICAAN TLDs such as `.TECHNOLOGY` and `.VERSICHERUNG` are being rejected by the EmailField.

Also there are the international domains that are encoded as `XN--CLCHC0EA0B2G2A9GCD` (Singapore, aka .சிங்கப்பூர்)

This adds a new TLD into the tests and extends the RegEx out. Something further to consider is accepting UTF-8 emails like "someone@company.சிங்கப்பூர்" but that's outside the scope of this humble PR.