libsass 3.0.2

Massive update for libsass. Has been merged into the core Sass repository on Github now, hence the homepage and url shifts.

Closes #34291.
Sorry, I usually remove only the revisions but I wasn't sure if given the massive bump it'd be kinder on the bot to have it deal with the ``` :any ``` bit itself or remove it and let it assess it afresh :confused: