Introduce `amd64v3` in the list of supported archs. NOTE: this may require additional validation, so please use this PR as a conversation starter/feature request if further work is required across the craft components. --- - [x] I've followed the [contribution guidelines](https://github.com/canonical/rockcraft/blob/main/CONTRIBUTING.md). - [x] I've signed the [CLA](http://www.ubuntu.com/legal/contributors/). - [x] I've successfully run `make lint && make test`. - [x] I've added or updated any relevant documentation.