Feature: Support parsing `TrueColor` from RGB string

[Dhruv Bhanushali]

Problem

Currently the from_str function supports parsing color names to Color enum based on the names. But this function does not parse TrueColor.

https://github.com/mackwic/colored/blob/11ffd20e7b5d1b48e4de7bb78ced26131ae5e114/src/color.rs#L88

Expectation

Given a string like rgb(<u8>,<u8>,<u8>), from_str should support parsing it to a Color::TrueColor instance.

Suggestion

In a project of mine, I've used a regex check to determine if the string matches the specific pattern and converts it to Color::TrueColor. A refined version of this could be added in the crate to be supported out-of-the-box.

let true_color = Regex::new(r"(?x)^
    (?:bg:)?
    rgb\(
        (?P<red>\d{1,3}),\s?
        (?P<green>\d{1,3}),\s?
        (?P<blue>\d{1,3})
    \)
$").unwrap();

let mut color: Option<Color> = None;
if let Some(caps) = true_color.captures(style) { // RGB colors
    let channels: Vec<u8> = vec!["red", "green", "blue"]
        .into_iter()
        .map(|x| caps[x].parse().expect("Must be int between 0 and 255."))
        .collect();
    color = Some(Color::TrueColor { r: channels[0], g: channels[1], b: channels[2] });
}

[Spenser Black]

It kind of looks like you're parsing a CSS color format into a Color instance. IMO it might be better for some sort of Color::from_str implementation to support all CSS color formats, so rgb(0, 0, 0), #000000, and black would all parse to Color::TrueColor{ r: 0, g: 0, b: 0 }.

BTW there are crates that handle the bulk of the work, like cssparser and css-color from a quick search, if this is reasonable. Maybe locked behind a feature called parsing or something?