[feature request]: change spinner color

[silvioprog]

Hi.

It would be nice an option allowing to change the spinner color, something like ora does:

cheers

[FGRibreau]

Hello @silvioprog, I will happily accept a PR for this along with tests :)

[ad4mx]

I could make a PR for this, I'm not sure if i could use another crate for colors or if i should stick with color escape codes.

[FGRibreau]

@ad4mx I'm ok if you leverage https://crates.io/crates/termcolor :)