feat: support regex in filter

[janlent1]

Makes running css-loader with advanced filter settings in worker possible.

This PR contains a:

• [ ] bugfix
• [X] new feature
• [ ] code refactor
• [ ] test update
• [ ] typo fix
• [ ] metadata update

Motivation / Use-Case

For thread-loader, setting functions as options is not allowed yet, but regex is. Therefore, supporting regex as a filter option for css-loader enables us to use the loader parallelized.

Breaking Changes

Additional Info

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (797042c) 95.78% compared to head (4ca3a75) 95.78%.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1555   +/-   ##
=======================================
  Coverage   95.78%   95.78%           
=======================================
  Files          10       10           
  Lines        1185     1187    +2     
  Branches      456      457    +1     
=======================================
+ Hits         1135     1137    +2     
  Misses         41       41           
  Partials        9        9           

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.