Gives back tags based on RGB code if it's light or dark

isColourDarkOrLight.ts

    public isColourDarkOrLight(rgb: number[]): 'light' | 'dark' {
        // RGB to HSP equation: http://alienryderflex.com/hsp.html
        const [r, g, b] = rgb;
        const hsp = Math.sqrt(
            0.299 * (r * r) +
            0.587 * (g * g) +
            0.114 * (b * b)
        );
        return hsp > 127.5 ? 'light' : 'dark';
    }