Update to Pandas v3.0

[zaneselvans]

Pandas v3.0 should come out during the summer of 2024.

• The biggest change is deeper integration of Arrow, which should give us much better rich dtype support and potentially better performance if we move toward using Arrow as our Pandas backend, which would also dovetail nicely with our use of PyArrow to output Parquet files.
• It's a major release and we use Pandas a ton, so we should expect breakage. We have a lot of warnings right now, and there are deprecations that we'll need to address.