Pandas 3 compatibility

[davetapley]

Just to get ahead of it, Pandas 3 nightly builds are at:

pip install --pre --extra-index https://pypi.anaconda.org/scientific-python-nightly-wheels/simple pandas

Once #175 is in I'll add 3 to here and report back:

dataretrieval-python/pyproject.toml

Line 23 in 16ee161

"pandas==2.*",

but anecdotally on my project I'm using pandas == 3.0.0.dev0+2094 and all seems pretty good ✅