Python 3.12 support

[adamltyson]

Describe the use case that is addressed by this feature.
We are currently updating BrainGlobe to Python 3.12. Two of our packages rely on AllenSDK, but but it can't be (easily) installed on Python 3.12. Some of the dependencies are pinned to fairly old versions, which causes errors on the newest versions of Python.

Describe the solution you'd like
For the package to be easily pip installable on Python 3.12. Ideally without maximum versions of dependencies for compatibility with other packages.

Describe alternatives you've considered
We could remove the AllenSDK dependency, but we'd rather keep it in, and ideally leverage it more over time.

Additional context
it would be fantastic if this package could follow the Scientific Python ecosystem dependency policy. I appreciate that keeping a large package up to date isn't an easy task, but staying at the bleeding edge seems to unfortunately be the only way to maintain compatibility between packages.

Thanks!