Fix several deprecation warnings in pandas 2.1 which became actual errors in 2.2

[bixbyr]

Fix for #156 in response to several minor pandas api changes. Tested with Django 4.2.9 and pandas 2.1.0.

[chrisdev]

Thanks @bixbyr some tests are failing. I I think we can ignore the Python 2.7 but apparently the for newer versions the pandas the testing module has been deprecated so we need to do our own makeTimeDataFrame

[jayvdb]

ping @bixbyr , will you be able to do the extra work requested by @chrisdev to get the CI to pass?

[bixbyr]

I added a commit which fixes the things which broke in 2.2. The moral of the story is don't rely on non-public parts of pandas. I think my pull request is correctly updated with 2 commits now instead of 1? I've never actually tried committing to a public repo before, weird as that sounds :)

Hopefully the maintainer can decide if we pass the tests now, and if the day has come to deprecate support for python 2 and pandas < 1.0 because seriously.

[chrisdev]

@bixbyr sorry for taking so long to respond. Was down with COVID! I thought this thing had gone away but its still around Still recovering so give me a few days.
Yes I think we should just deprecate support for python 2. Although last time I tried to do so there was a bit of an uproar. But think this time it goes!

[bixbyr]

Any updates? Will this be approved and a new version released?