Update email regex to match gTLDs (ziishaned#32)

Author: tibor

README.md

@@ -478,7 +478,7 @@ line. And because of `m` flag now regular expression engine matches pattern at t
 * *Alpha-numeric characters*: `^[a-zA-Z0-9]*$`
 * *Alpha-numeric characters with spaces*: `^[a-zA-Z0-9 ]*$`
 * *Password*: `^(?=^.{6,}$)((?=.*[A-Za-z0-9])(?=.*[A-Z])(?=.*[a-z]))^.*$`
-* *email*: `^([a-zA-Z0-9._%-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,4})*$`
+* *email*: `^([a-zA-Z0-9._%-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,})*$`
 * *IPv4 address*: `^((?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?))*$`
 * *Lowercase letters only*: `^([a-z])*$`
 * *Uppercase letters only*: `^([A-Z])*$`