[Bug] Semver breaking change in last release

[GeorgeTaveras1231]

Version 6.3.0 removes @storybook/addon-knobs/register entrypoint which was present in version 6.2.9, and needed for older versions of storybook. This caused an unexpected breaking of the build on my app.

I think the appropriate way to handle this would be to deprecate 6.3.0 (via npm deprecate) to avoid consumers accidentally upgrading to this version, and releasing either 6.3.1 with the register file included, or 7.0.0 with the package as it is.