Re-chartering the WebGPU Working Group for a "Living Spec"

Hey all,

The intent for the WebGPU and WGSL specification has always been that they
would be "living specs" because there is no obvious end to the features to
add, especially as hardware keeps evolving. Previously we achieved this by
having working drafts continuously published. However this doesn't make
WebGPU/WGSL standards but just specifications hosted by the W3C, instead we
should strive to reach Candidate Recommendation (CR) status while keeping
the "living spec" aspect.

For more context, please read "François Daoust" email titled "Candidate
Recommendation and Living Specs". He outlines how a CR can be used as a
living spec with continuously published drafts and periodic (~yearly)
snapshots. To do this we need to edit the GPU for the Web WG charter
<https://www.w3.org/2022/11/gpuweb-charter.html> to allow for this
mechanism. This is a head's up that the group will likely do that, which
will call for a comment period etc. However feel free to comment about this
early if you see issues with allowing Living Spec CR in the charter!

Cheers,

Corentin