Remove smtp_user regex validation from Penpot (#434)

The regex validation breaks certain email delivery services, as they don't simply use mail addresses.

AFAIK, there is no limitation on SMTP usernames, when it comes to authentication.

public/v4/apps/penpot.yml

@@ -128,7 +128,6 @@ caproverOneClickApp:
         - id: $$cap_smtp_username
           label: SMTP username
           defaultValue: user@example.com
-          validRegex: /^[a-zA-Z0-9.!#$%&’*+/=?^_`{|}~-]+@[a-zA-Z0-9-]+(?:\.[a-zA-Z0-9-]+)*$/
         - id: $$cap_smtp_password
           label: SMTP password
           defaultValue: