possible false positive attribute with namespace "serif:id"

@darylldoyle

Do you see a security problem in the observance of namespaces for attributes?

e.g.: serif:id="Page 1”

<g id="Page-1" serif:id="Page 1">

In my opinion, this should not trigger a “Suspicious attribute ‘serif:id’” message, as the “id” attribute is already on the whitelist.

https://github.com/darylldoyle/svg-sanitizer/blob/master/src/data/AllowedAttributes.php#L56

[ohader]

Can you please provide a simplified but complete example how serif:id is used? Please provide the whole SVG data - I'm basically interested in the XML namespace and the schema definition. Thanks in advance!