GitHub action to publish typenum_macro

[paholg]

The proc_macro branch includes a typenum_macro crate created by @jerry73204. In order to merge that branch to main and publish it, we need to publish the typenum_macro crate.

[HastD]

What's the status of this? It'd be nice to have these macros available.

[paholg]

It requires some work to restructure the project into a workspace, and to update the publish github action to be able to publish the crates independently.

Anyone is welcome to put up a PR.

[paholg]

With the const-generics feature, I'm not sure how valuable this macro is. You may want to try that?

https://docs.rs/typenum/latest/typenum/generic_const_mappings/type.U.html