chore: bump version to 6.0.0-alpha.0

[jcesarmobile]

last time lerna wasn't able to bump the major version for the first alpha, so doing it manually so we can release alphas

[markemer]

I think lint is failing since we haven't published 6 alpha's yet.

[jcesarmobile]

yeah, we shouldn't merge this until we are about to release the first alpha.
The publish script calls sync-peer-dependencies which would set the peer dependencies to also 6.0.0-alpha.0 and once they are published it will stop erroring