Update development release version to 0.10.0.dev0

[harperj]

In order for downstream packages to make use of the latest
pre-release features, we can pre-release versions of our packages.
For packages ending in devN pip will not install that package
version by default. This change manually updates our package version
to a development version with the idea that we can manually perform
development versions with the potential for future automated / nightly
dev releases.

[ervteng]

Looks fine to me - I'd just update the release checklist to be sure to remove the dev from the setup.py. There's also the possibility of a major release becoming a minor release if a certain feature doesn't make it in by the end of the month.

What do you think about auto-ticking the dev version, e.g. https://the-hitchhikers-guide-to-packaging.readthedocs.io/en/latest/specification.html#development-releases?

[ervteng]

Looks OK

[harperj]

@ervteng I was thinking of this as a stepping stone towards automatically ticking the development version -- we should confirm the process works manually and then potentially add it to an automated process. I think it's OK if we have 0.10.devX be at the same position as 0.9.2 if something changes with our release schedule.

Will update the release checklist.