[CT-2020] [Bug] replace bump version dependency with bump2version

[emmyoop]

Change Required

While everything still works, bumpversion has been abandoned and we should now use bump2version, which is what is being use under the hood anyways.

Listed as a dependency in dev-requirements.txt and used as part of the version bump. Will need to test this change against the release process, specifically the version bump piece. Will also require changes to the nightly release tests.

Needs to be done for all adapters as well.

Complication

We bump all version numbers that match, not just the expected current version. So we can inadvertently bump dependencies and break ourselves. Ideally we could list the current version in a single place and not multiple files. That would make it easier to bump.

[dbeatty10]

If we keep maintaining dbt-database-adapter-scaffold, then we should update here also.

[jtcohen6]

Estimated with @colin-rogers-dbt @McKnight-42. This is important, potential future blocker to successful release, we should try to knock it out before we get there. Not complex work but definitely some toil/tedium.

[emmyoop]

I'm not really sure what's going on with the project. There's a thread here on future ownership and the resolution still seems somewhat unclear. It might also be good to look at other alternatives.

[emmyoop]

bump2version is also abandoned now and recommends to move to bump-my-version.

bumpversion is the cause of a bug where anything that matches the current dbt version will also get bumped. See #9107