Support for updated $dimension and $duration types

[AndreBarr]

The $dimension and $duration types formats have been updated by this proposal:
design-tokens/community-group#244

Will this support be added?
I could possible contribute this update as well

[lukasoppermann]

Hey @AndreBarr,

YES, this should be supported.

And we probably need to adjust it in all transforms for composite tokens that use dimensions as well.

I would really appreciate a PR.

I think it is best to keep supporting the old behavior but return a console.error saying that using this format is deprecated and will be removed in one of the next major releses.

[lukasoppermann]

Hey @AndreBarr are you still up to create a PR for this?