[2.x] Adds toBeEmail() Expectation

[LucasLaurens]

What:

• [ ] Bug Fix
• [x] New Feature

Description:

This PR adds a toBeEmail() expectation, to validate whether a value is a valid EMAIL.

Related:

expect('test@example.com')->toBeEmail();
expect('test@localhost')->not->toBeEmail();

[LucasLaurens]

If the PR is accepted, I could create one for documentation.

[LucasLaurens]

I also have a question. Do I need to update the snapshots? This would seem normal if this feature is accepted.

[LucasLaurens]

I hadn't seen it before. But my PR matches this one exactly. So it doesn't make sense anymore.

[LucasLaurens]

Perhaps in the long term, if the intention is to add an expectation on the email, this could be improved with a DNS check.

[!NOTE] I was able to extend an expectation on a personal project where I check for a specific use case the validity of the email according to an RFC and DNS validation.

/** DNS Validation */
$dns = new DNSCheckValidation();

if (
    !$dns->isValid(
        email: $value,
        emailLexer: new \Egulias\EmailValidator\EmailLexer()
    )
) {
    return false;
}