Use Xcode's native Color Literals feature to add hex colors easily and natively.
Type Color Literal
into your code and let Xcode autocomplete do the rest.
The color picker UI will allow you to paste in a Hex Color: #FF9300
The git diff of the macro will show RGB values rather than hex:
let orange = #colorLiteral(red: 1, green: 0.5763723254, blue: 0, alpha: 1)
But it's still an easy way to paste in hex without any 3rd party tools or extensions.