Support Border Color Utilities

[deadcoder0904]

I thought it isn't supported as autocompletes weren't there so I searched & stumbled upon 2-3 issues which lead me to this PR by @adamwathan which adds support for custom border colors.

Basically it should autocomplete when I type border-t- like:

<div class="border-t-blue-500 border-b-pink-300">

[BennaceurHichem]

The same problem for, it doesn't work also when I use it

[sametweb]

I came across the same issue. Hope they're added soon.

Don't know how to do TailwindCSS without this extension. Great job!

[bradlc]

Hey @deadcoder0904. Per-side border colour completions are supported when using tailwindcss v3. I'm going to close this as it's unlikely we will be back-porting this for v2's JIT mode.