Sourcemaps broken in latest v1.6.0

[danspam]

The latest version of this plugin no longer allow sourcemaps to be generated correctly. According to the docs, in clean-css v4.0 and above they changed the api for using sourcemaps and passing the sourcemaps into the options as this plugin does no longer works.

If I understand correctly the sourcemaps need to be passed as a paramater into the minify() method instead. See docs.