Prepublish task fails on valid Haml

[hibariya]

from: https://github.com/idobata/idobata-hooks/pull/80#discussion_r120040854

IMO the template is valid Haml. But yarn run prepublish fails.

➤ cat lib/hooks/docker-hub/help.html.haml
%dl
  %dt Usage
  %dd
    See <a href="https://docs.docker.com/docker-hub/webhooks/" target="_blank">Webhooks for automated builds | Docker Documentation</a>.
➤ yarn run prepublish
yarn run v0.24.6
$ rm -rf app && broccoli build app 
SyntaxError: (Haml): missing ) after argument list
    at Function (<anonymous>)
...

There is a workaroud: when I replace quotes of attribute values in <a> from " to ', it works.