fix: add generator for arbitrary sized arrays

[camshaft]

There were a few recent changes that broke the build in s2n-quic:

• In Fix #[derive(TypeGenerator)] #126, the generic bounds in derives were changed and broke implementations using arbitrary sized arrays:

  #[derive(TypeGenerator)]
  struct Thing<T, const LEN: usize> {
    data: [T; LEN],
  }

  This is because before we generated a where clause for the whole field type:

  where [T; LEN]: TypeGenerator

  and now we generate it just for the generic type:

  where T: TypeGenerator

  To work around this, I've implemented TypeGenerator for all array lengths, which is a good idea to do anyway.

• In do not require importing bolero_generator or TypeGenerator in order to derive #109, it was set up to prioritize importing TypeGenerator from the bolero crate, if possible. This causes issues for crates like s2n-quic-core where we export TypeGenerator impls with a feature flag and only use bolero as a dev-dependency. I've swapped the priorities and this is resolved.

To try and prevent this kind of breakage in the future, I've added a workflow to test s2n-quic against any bolero changes. Note that the versions do need to match (they currently don't since the s2n-quic update is blocked on these issues) but I was able to test locally and make sure these are fixed. Moving forward, we should still be able to catch issues before bumping bolero versions.

[adpaco-aws]

Oops! Sorry for breaking the build in s2n-quic 😥

Just a few comments/questions.

[adpaco-aws]

Thanks, @camshaft !