Bypass release notes requirement on 0.0.x

[MilesCranmer]

I was wondering if the breaking change release notes requirement could be lifted for packages when they are on 0.0.x? Packages on 0.0.x are pre-alpha so it feels a bit overkill to require this at that stage, since there is no way to mark a non-breaking change at that point in the development cycle.

Why register a 0.0.x package?

0.0.x is useful for packages that are still heavily iterating on the API, or are in an experimentation stage, but still have use as a dependency, or perhaps need real-world testing (via being registered). The transition from 0.x.y to 0.(x+1).0 often carries an expectation of few major API changes. Using 0.0.x is a nice way to indicate that there shouldn't be any expectations of changes from one version to the next.

Of course one still might like to indicate breaking changes between versions. But I think we shouldn't require it for 0.0.x.