Pretty good, though <domain> should end with <alpha> 2..*
Note that your version is not actually the same, as it accepts all alphabetic characters, not just ASCII ones. Which put it much closer to RFC 6532, but still not exactly there due to the quoting rules in usernames. Which get pretty hairy. See [1] for an implementation of RFC 822, which is a simpler version of the modern standard, for a regex to validate email in Perl 5.
Note that your version is not actually the same, as it accepts all alphabetic characters, not just ASCII ones. Which put it much closer to RFC 6532, but still not exactly there due to the quoting rules in usernames. Which get pretty hairy. See [1] for an implementation of RFC 822, which is a simpler version of the modern standard, for a regex to validate email in Perl 5.
[1]: https://metacpan.org/source/RJBS/Email-Valid-1.200/lib/Email... trigger warning: bleeding eyes