feat: support *.css files by default

[elycruz]

Currently (with #131 ) the plugin supports *.css files (by adding inclusion of them (via option include)), however it might be cumbersome to have to specify you want to support *.css files, in given projects, due to possibly not remembering that you have to specify support for *.css file extension.

Acceptance Criteria

• Add **/*.css in the plugins defaultIncludes array.
• Unit tests showing a working example.

[08AHAD]

please assign me this issue

[elycruz]

Assigned.

[elycruz]

We're not going to attempt to support *.css to *.css compilation for now as 'dart-sass', and other sass-only compilers don't directly support css imports (@import url('...*.css') - We're leaving this functionality to other plugins/libraries to handle.