Uncap numpy version to fix installation on Python 3.12

[architkulkarni]

The numpy version was capped at <1.25, which fails to install on Python 3.12 (numpy/numpy#23808). This PR uncaps the numpy version. The reason for the cap was some version compatibility issue with numba, but numba doesn't seem to be imported anywhere currently.

Closes #19, closes #16

Tested with

conda create --name test python=3.12 -y
conda activate test
pip install -e .

[jonathan-taylor]

Uncapping numpy requirement (previously there for a numba issue)