Support HWB string

[omgovich]

https://drafts.csswg.org/css-color-4/#the-hwb-notation

[codecov-commenter]

Codecov Report

Merging #42 (69d4f8f) into master (0fda771) will not change coverage. The diff coverage is 100.00%.

@@            Coverage Diff            @@
##            master       #42   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           33        34    +1     
  Lines          403       419   +16     
  Branches        69        72    +3     
=========================================
+ Hits           403       419   +16     

Impacted Files	Coverage Δ
src/colorModels/hwb.ts	100.00% <100.00%> (ø)
src/colorModels/hwbString.ts	100.00% <100.00%> (ø)
src/plugins/hwb.ts	100.00% <100.00%> (ø)

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[github-actions[bot]]

Size Change: +273 B (+3%)

Total Size: 8.85 kB

Filename	Size	Change
./dist/plugins/hwb.js	887 B	+273 B (+44%)	🚨

ℹ️ View Unchanged

| Filename | Size | Change | | :--- | :---: | :---: | | `./dist/index.js` | 1.9 kB | 0 B | | `./dist/plugins/a11y.js` | 459 B | 0 B | | `./dist/plugins/lab.js` | 1.03 kB | 0 B | | `./dist/plugins/lch.js` | 1.42 kB | 0 B | | `./dist/plugins/mix.js` | 965 B | 0 B | | `./dist/plugins/names.js` | 1.36 kB | 0 B | | `./dist/plugins/xyz.js` | 822 B | 0 B |

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