text: Title: Add more valid tags for CAA record
  Body: Hey,
  
  I updated my CAA record (issue and iodef), I wanted to add “issuemail”, for S/MIME certificates (https://www.rfc-editor.org/rfc/rfc9495.pdf), but I get a warning saying that the tag is invalid.
  The record works anyway, but if it were possible to remove the warning to avoid confusion, that would be nice.
  I also recently saw on a test on hardenize.com that there is an “issuevmc” tag, for BIMI certificates, which could be added at the same time.
  
  Thanks for your work !