v2-chore: Cleanup toward v2 release (#539)

* bump version to 2.0.0-a0

* Add empty embed dep group for backward compat

* update README

* use release-opt profile for building wheels

* remove action pinning, update some versions

* update to upload artifact v4

* normalize alpha version to not have hyphen in Python

* fix deps

* put wasm package in a directory so macos doesn't unzip it.

* update action versions

* update versions

* release-opt

* fix dep

* to macos 13

* only upload test images on failures

* upload wasm package as directory