fix: added support for colors for the sketch extractor

[jerradpatch]

Pull request for add sketch 69.2 support, and add some defaults when values are not provided in sketch.

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[zackbrown]

Hey Jerrad, thanks for this! I'd love to merge this — two issues:

1. Can you please sign the CLA?
2. Travis isn't detecting this PR, which seems to be an issue on their end. I'm pursuing this with them. Once it's back up and running, we can verify that tests pass.

[roperzh]

Chiming in, this looks great! thanks for the fix! to make the build pass you need to do two things:

1. This project doesn't support the optional chaining operator (yet!) please use an alternative here:
   

   diez/src/extractors/extractors/src/extractors/sketch.ts

   Line 324 in 43ae14f

   const alignment = mapNSTextAlignment(textStyle.NSParagraphStyle.style?.alignment || 0); //default value as of sketch v69.2

2. Fix the lint errors, you can automatically fix most of them with yarn fix.

[tomastrajan]

Any update on this ?