Relax color parser based on the current and upcoming CSS specs

[kimikage]

This adds supports for:

• fractional RGB values, e.g. "rgb(255.0, 0.0, 0.0)"
• fractional percentages, e.g. "rgb(1e2%, 34.5%, .6%)"
• more clamping, e.g. "hsla(0, -10%, 120%, 1.5)"
• hue angle units, e.g. "turn", "rad"
• case-insensitive function names, e.g. "Rgb(0, 0, 0)"

This throws an error when mixing percentages and numbers, e.g. "rgb(100%, 128, 0%)".
This also changes the type of the errors from ErrorException to ArgumentError.

Closes #431

[codecov]

Codecov Report

Merging #478 (d6bb85e) into master (81aaf1e) will increase coverage by 0.55%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #478      +/-   ##
==========================================
+ Coverage   91.88%   92.44%   +0.55%     
==========================================
  Files           9        9              
  Lines         937      979      +42     
==========================================
+ Hits          861      905      +44     
+ Misses         76       74       -2     

Impacted Files	Coverage Δ
src/parse.jl	97.47% <100.00%> (+3.97%)	⬆️

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[kimikage]

Benchmark

Linux (x86_64-linux-gnu) - Debian 10 on WSL2

Julia v1.6.1

target	before(v0.12.8)	after
"#C0FFEE"	251.870 ns (7 allocations: 352 bytes)	159.566 ns (5 allocations: 304 bytes)
"#C0FFEEaa"	268.553 ns (7 allocations: 352 bytes)	174.588 ns (5 allocations: 304 bytes)
"rgb(0,0,0)"	422.613 ns (7 allocations: 400 bytes)	409.000 ns (7 allocations: 400 bytes)
"rgba( 0, 11,222,0.45)"	714.925 ns (8 allocations: 432 bytes)	578.022 ns (8 allocations: 432 bytes)
"hsl(60,70%,80%)"	572.826 ns (7 allocations: 416 bytes)	459.898 ns (7 allocations: 416 bytes)
"LightGoldenRodYellow"	519.251 ns (6 allocations: 240 bytes)	347.907 ns (6 allocations: 240 bytes)
"lightgoldenrodyellow"	341.951 ns (3 allocations: 64 bytes)	185.286 ns (3 allocations: 64 bytes)

Windows (x86_64-w64-mingw32) - Windows 10

Julia v1.6.1

target	before(v0.12.8)	after
"#C0FFEE"	358.962 ns (7 allocations: 352 bytes)	242.280 ns (5 allocations: 304 bytes)
"#C0FFEEaa"	369.903 ns (7 allocations: 352 bytes)	261.408 ns (5 allocations: 304 bytes)
"rgb(0,0,0)"	628.902 ns (7 allocations: 400 bytes)	657.576 ns (7 allocations: 400 bytes)
"rgba( 0, 11,222,0.45)"	1.480 μs (8 allocations: 432 bytes)	1.250 μs (8 allocations: 432 bytes)
"hsl(60,70%,80%)"	805.882 ns (7 allocations: 416 bytes)	708.784 ns (7 allocations: 416 bytes)
"LightGoldenRodYellow"	878.723 ns (6 allocations: 240 bytes)	544.211 ns (6 allocations: 240 bytes)
"lightgoldenrodyellow"	692.199 ns (3 allocations: 64 bytes)	342.056 ns (3 allocations: 64 bytes)