Python 3.11,3.12 conda install fails.

[benjeffery]

Seems sgkit can't be installed on 3.12 due to cbgen:

Pinned packages:

• python 3.12.*

Could not solve for environment specs
The following package could not be installed
└─ sgkit 0.8.0 is installable and it requires
└─ cbgen with the potential options
├─ cbgen [1.0.0|1.0.1] would require
│ └─ python >=3.7,<3.8.0a0 , which can be installed;
├─ cbgen [1.0.0|1.0.1] would require
│ └─ python >=3.8,<3.9.0a0 , which can be installed;
├─ cbgen [1.0.0|1.0.1] would require
│ └─ python >=3.9,<3.10.0a0 , which can be installed;
└─ cbgen 1.0.1 would require
└─ python >=3.10,<3.11.0a0 , which can be installed.