[FEAT] Add support for custom registry

[Jannik-dev]

Some companies are using their own registry (with tools such as https://pub.dev/packages/unpub).

It would be beneficial to allow custom registries with a configuration like:

"semantic-release-pub",
{
  "host": "https://my-registry.com"
}

[zeshuaro]

Thanks for raising this. Do you have any idea how authentication would work for the example custom registry you shared?

[Jannik-dev]

This seems to be the documentation, but the example unpub does not currently support this (see pd4d10/unpub#36)

[zeshuaro]

Currently, the plugin is implemented with the auth mechanism you linked. I would prefer if other custom registries also support this or have something as simple as basic auth so that we don't end up with having multiple custom auth mechanism for different registries.