chore(py3): remove outdated python2 utf8 hint

[Rotzbua]

[svenevs]

This looks great, I want to wait on this or any py2 dead code elimination stuff. The next release is going to prioritize

• Fixing the packaging requirements
• Adding concepts
• A few small issues that can be fixed with minimal effort

I want to do this with as few code changes as possible, with the hope that after releasing no flood of issues come in saying I broke something. If all goes well, then I will want to clean the crap out of this codebase and will start here :slightly_smiling_face:

Just wanted to give you a heads up that while I really appreciate your help getting this all cleaned up, I want to be very careful about how I update what and when. There's a lot of ... shenanigans ... in graph.py in particular, and I worry about doing a release that adds new features and does huge backend changes.

While I don't see any reason why the changes here would cause problems, I want the next release to have as small a diff as possible to make it easier to bisect if the new features actually break something.