Support ColorValue type from RN 0.63

[Saadnajmi]

https://github.com/react-native-svg/react-native-svg/blob/b2e2c355204ff4b10973d3afce1495f7e4167ff7/src/lib/extract/types.ts#L11

Previously, React Native (>0.63) defined colors as a number or string. With the introduction of Platform Color in React Native 0.63, there is a new React Native ColorValue type that extends the definition to allow platform specific semantic colors.

It would be nice to change RN-SVG's local "Color" type to just match the React Native one.

[Saadnajmi]

Looks like this is a dup of #1391

[WoLewicki]

Since #1561 has been merged, should we close this issue?

[Saadnajmi]

Yeah, I think that makes sense. I think there's still an improvement to be made where RN-SVG relies on React Native's ColorValue type and RCTConvert methods, rather than redefining them in it's own repo. However, the issue of supporting PlatformColor is fixed, and my suggestion is "potential improvement" rather than bug, so I'm happy to close this issue.