Make Pastas compatible for Pandas 3.0

[raoulcollenteur]

Describe the proposed feature
Pandas 3.0 will be released this summer. Some pattern won't work anymore after 2.2, so once we accept 3.0 we need to bumo minimum version to 2.2.

• replace "A", "A-MAR", and "M" by "YE", "YE-MAR", and "M"
• pyarrow will be the default.
• test with pd.options.mode.copy_on_write = True
• .. add more here

[martinvonk]

Pandas 2.0.3 gives a KeyError "YE" etc. Additionally, Pandas has no support for Python 3.8 since version >=2.1. So that's why the Python 3.8 tests failed with the "YE". So if we drop Python 3.8 only Pandas >=2.1 can be installed.

See also https://pandas.pydata.org/docs/dev/whatsnew/v2.1.0.html and pandas-dev/pandas#9586

Implemented Series.dt.is_month_start, Series.dt.is_month_end, Series.dt.is_year_start, Series.dt.is_year_end, Series.dt.is_quarter_start, Series.dt.is_quarter_end, Series.dt.days_in_month, Series.dt.unit, Series.dt.normalize, Series.dt.day_name(), Series.dt.month_name(), Series.dt.tz_convert() for ArrowDtype with pyarrow.timestamp (GH 52388, GH 51718)

[raoulcollenteur]

If I understand well @martinvonk, after we dropped 3.8 support, we should also add pandas >=2.1 ? Kind of for it if that solves this issue..

[raoulcollenteur]

2.1 also gives an Error for "YE" and alike. So we need to bump to 2.2.1 as the minimum version. Let's first do this with Pastas 2.0