ROOT_TAGS_REGEX fails to recognise mjml tag with attributes

[samstickland]

This is the opening MJML tag I get from a Passport export <mjml owa="desktop" version="4.5.1">

ROOT_TAGS_REGEX is /<mjml>.*<\/mjml>/mi so it fails to match.

[samstickland]

Can we change the regex to this?

ROOT_TAGS_REGEX = %r{<mjml((\s+\w+(\s*=\s*(?:".*?"|'.*?'|[\^'">\s]+))?)+\s*|\s*)/?>.*<\/mjml>}im

(based on https://haacked.com/archive/2004/10/25/usingregularexpressionstomatchhtml.aspx/)

[samstickland]

Actually there might be more general compatibility issues with MJML v4?

[m-basov]

@samstickland I believe we might use something simpler for matching root tag because we don't care about the attributes. So something like <mjml[any symbol]> should do the work.I will gladly accept the PR with it if you want to help 😃

[m-basov]

@samstickland actually, it was pretty fast to fix, sorry for the late response. Please let me know if you will have any issues with MJML v4 and even better – submit the PR, they are greatly appreciated :)