feat: Support Pandas 2

[Flix6x]

• Requires Support Pandas 2 SeitaBV/timely-beliefs#131
• Requires Support Pandas 2 SeitaBV/timetomodel#28
• Figure out why linear_optimization.py now needs inclusive="both" rather than inclusive="left" -> BUG: Timedelta created by to_timedelta does not add correctly to datetime in Pandas 2 pandas-dev/pandas#53643

[nhoening]

So we still pin to 1.5.3 right? (requirements/app.txt says: pandas==1.5.3`)

• Have you run the tests with pandas 2.0 installed? (I'd be interested in the difference in timing btw :)
• Why not move up the pin now? It's by now mostly for developers and the Docker image. If you opt to wait, it means you want to gather experience?

[Flix6x]

Why not move up the pin now?

I want to, but I'm struggling to do this successfully with any of our make commands. Can you take a look? I shouldn't manually change the requirements/app.txt, right?

[nhoening]

Yes, that would update many others, as well. Best to update all new pins right after the next release.

But maybe you can pip-install pandas 2, to see if our tests pass (and are faster)

[Flix6x]

Thanks. The results:

• 208.13s on Pandas 1.5.3
• 202.47s on Pandas 2.0.2

I did notice a small fix was needed with some of the new reporter functionality. So I pushed one more commit.

[nhoening]

* 208.13s on Pandas 1.5.3
* 202.47s on Pandas 2.0.2

Ah, no big speed gain here :)
But we have very little test data, of course.