Fix/numpy2 compatibility

[p-snft]

It's almost impossible to have doctests that work with both, numpy 1.x and numpy 2.x: The string representations changed to include the data type. Example:

> data = numpy.array([1,2,3])
> print(data[1])  # no longer prints "2"
np.int64(2)

Introducing a lower bound to Pandas as well allows to remove Pandas <2.2 compatibility code.