ADKT FutureWarning

[numersoz]

Hi,

This error is annoying, can we fix this. Should be simple.

adtk/data/_data.py:164: FutureWarning: iteritems is deprecated and will be removed in a future version. Use .items instead

[vincentl-met]

It's now even mandatory for pandas >=2.0.0. It's breaking many functions such as plot from adtk.visualization