Correct the regexp for kewordish css property which hold hex values

[asok]

Loofah::HTML5::Scrub.scrub_css("background: #0000A") # => ""

Should behave the same as

Loofah::HTML5::Scrub.scrub_css("background: #0000a") # => "background:#0000a;"

[flavorjones]

THanks for submitting this PR! I'll take a look as soon as I can, this is a super-busy week for me.

[flavorjones]

@asok I noticed that this change doesn't have any test coverage. Would you mind adding a unit test to prevent regressions?

[asok]

I've added one, I hope this is something you've hoped for.

[flavorjones]

@asok Thanks for writing up some tests. Though the ones in your commit were using assert instead of assert_equal, I was able to easily fix them and they're running through CI now.

[flavorjones]

CI went green, I've merged and this will be in v2.3.0 when it ships.

[flavorjones]

v2.3.0 has been released.