add: postcss logo

[MoritzBru]

Not sure if Compiler is the proper category.

See https://github.com/postcss/brand/tree/master for logo source and license

[vercel]

@MoritzBru is attempting to deploy a commit to the Pablo Hdez's projects Team on Vercel.

A member of the Team first needs to authorize it.

[pheralb]

Thanks 🚀🚀

[MoritzBru]

I further reduced the number precision in SVGOMG to reduce the size of the wordmark version.
Checks are passing now and visually its still fine.

[pheralb]

Thanks 🚀