Upgrade Dependencies

[FlatMapIO]

There was only one test failure, but after a simple modification, all tests passed.

[thetarnav]

Updating dev deps and tests makes sense, but since there are no code changes, I would prefer to not release a new version that just increases minimal dependency versions for no real reason.

[FlatMapIO]

I agree with your point, but both motionnoe and solid are quite stable, so it's also necessary to update the ecosystem every few months to keep the project fresh :)