update 'quotes' rule for 3.0

[MelSumner]

For 'next' branch:

Now that .html files are included, the quotes rule (you must use double quotes in templates) is throwing a false positive over acceptable lines.

Example:

{{content-for 'head'}}
{{content-for 'head-footer'}}

These should be allowed.

[rwjblue]

Hmm, I don't think we should allow those arbitrarily. Applications are manually opting in to "stylistic" configuration, which requires double quotes (Note: it is not in default recommended set).

I also think it would be perfectly fine to update the ember-cli blueprint to use double quotes in the blueprint (to reduce the manual changes needed for new projects that want to use stylistic config).

[MelSumner]

ok, I'll close this as not a bug then. Thank you for the feedback!