bump version and fix ci

[almarklein]

• Bump version.
• Fixed a small bug (we used np.bool but that's deprecated).
• Update CI to test for py38 -py312. (dropped 3.7 out of convenience, because black on py37 behaves differently).
• I did not fix the CI build for circle-ci, because my bandwith is limited and I don't feel like looking into expired credentials right now 🤷

[almarklein]

@emmanuelle FYI, will push a new tag and push to pypi.

[almarklein]

On the release process in the readme, the last bullet says "Bump version of dash-slicer in dash-docs". I can't remember how that works, or whether that's still necessary.