feat: add support for less-loader

[janlent1]

Enables threadloader to be used for less-loader

This PR contains a:

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

Motivation / Use-Case

We would like to paralllelize expensive less transpilation.

Breaking Changes

Additional Info

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: janlent1 (c6cfd77, e3b2329, f4bc1c2)

[codecov]

Codecov Report

Attention: Patch coverage is 1.96078% with 50 lines in your changes missing coverage. Please review.

Project coverage is 19.45%. Comparing base (0b0d8d2) to head (f4bc1c2).
Report is 8 commits behind head on master.

Files with missing lines	Patch %	Lines
src/WorkerPool.js	2.50%	34 Missing and 5 partials ⚠️
src/worker.js	0.00%	11 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #198      +/-   ##
==========================================
- Coverage   21.23%   19.45%   -1.78%     
==========================================
  Files           8        8              
  Lines         504      555      +51     
  Branches      108      118      +10     
==========================================
+ Hits          107      108       +1     
- Misses        348      393      +45     
- Partials       49       54       +5     

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