Change rgb to RGB in css

[fareesh]

Solves some older SASS compilation issues where the new css rgb function conflicts with the SASS function of the same name

[AllanJard]

Thanks for the PR. I don't think I've encountered a conflict with this before. What version of SASS is causing the issue?

[fareesh]

I'm seeing an error with sass 1.68.0

Relevant StackOverflow post: https://stackoverflow.com/questions/71805735/error-function-rgb-is-missing-argument-green-in-sass

[AllanJard]

Sorry for the long delay in replying here. If you use a more up to date version of the sass package, does it then work? I've got DataTables being built with 1.75.0 at the moment and 1.77.4 appears to be the current release (at the time of writing).

One thing with this fix, is that the output in this repo is actually generated by SASS! The DataTables sorce repo gets compiled by SASS, and then committed to this repo (and others). So the change wouldn't be as simple as updating this repo unfortunately.

I'm inclinded to say that if it works with newer SASS packages, then we'll leave it like that.