Add official support for Python 3.12

[shakedzy]

As Python 3.12 was released, dython needs to be tested for it too.

[Pesche007]

Thanks for your work.

Just upgraded to Python 3 (running Pandas 2.1.1) and some future warings pop up

`import pandas as pd
from sklearn import datasets
from dython.nominal import associations

Load data

iris = datasets.load_iris()

Convert int classes to strings to allow associations

method to automatically recognize categorical columns

target = ['C{}'.format(i) for i in iris.target]

Prepare data

X = pd.DataFrame(data=iris.data, columns=iris.feature_names)
y = pd.DataFrame(data=target, columns=['target'])
df = pd.concat([X, y], axis=1)

Plot features associations

associations(df)`

C:\Users\User\AppData\Roaming\Python\Python310\site-packages\dython\nominal.py:708: FutureWarning: Setting an item of incompatible dtype is deprecated and will raise in a future error of pandas. Value '' has dtype incompatible with float64, please explicitly cast to a compatible dtype first.
inf_nan.loc[columns[i], columns[j]] = _inf_nan_str(ij)
C:\Users\User\AppData\Roaming\Python\Python310\site-packages\dython\nominal.py:709: FutureWarning: Setting an item of incompatible dtype is deprecated and will raise in a future error of pandas. Value '' has dtype incompatible with float64, please explicitly cast to a compatible dtype first.
inf_nan.loc[columns[j], columns[i]] = _inf_nan_str(ji)

[shakedzy]

@Pesche007 this seems to be a bug in Pandas, which was solved in version 2.1.2: pandas-dev/pandas#55025
Try upgrading Pandas and see if it is solved.