Drop support for Python 3.9

[jduerholt]

This PR drops the support for Python 3.9. It will go EOL this year (https://devguide.python.org/versions/) and causes especially trouble with Entmoot but also in other occassions.

cc: @TobyBoyne @LukasHebing

[jduerholt]

We have here some pyright issue, the old version (1.1.305) makes problems with py3.10 and throws errors which are not really errors. Switching to newer versions produces a lot of real errors, for which I do not have currently the time to fix. I would propose to merge it as is to get rid of the entmoot problems and handle the pyright stuff seperately. Maybe somebody is also volunteering. What do you think?

[bertiqwerty]

Thanks. Agreed.

[CompRhys]

We have here some pyright issue, the old version (1.1.305) makes problems with py3.10 and throws errors which are not really errors. Switching to newer versions produces a lot of real errors, for which I do not have currently the time to fix. I would propose to merge it as is to get rid of the entmoot problems and handle the pyright stuff seperately. Maybe somebody is also volunteering. What do you think?

I don't mind grinding through some linting errors, brainless work to do in the evening

[jduerholt]

I don't mind grinding through some linting errors, brainless work to do in the evening

Sounds great! Thanks @CompRhys. I would recommend to switch directly to the newest version then.

[CompRhys]

@jduerholt Will get to this either tonight or over the weekend to try clear the linting issues