Description of the change

Update the version of the CLI in preparation for a v4.0.0 release. This includes breaking changes to the CLI (emit-provider becoming emit-plugin and javy build -C dynamic requiring a plugin).

Why am I making this change?

I want to release the support for plugins for dynamically linked modules.

Checklist

• I've updated the relevant CHANGELOG files if necessary. Changes to javy-cli and javy-plugin do not require updating CHANGELOG files.
• I've updated the relevant crate versions if necessary. Versioning policy for library crates
• I've updated documentation including crate documentation if necessary.