Resolve element replicas in FloorPlot

[giadarol]

Changes:

• Resolve element replicas in FloorPlot

[giadarol]

I also added a requirement for the version of pint as users reported that that xplt stopped working after upgrading to numpy 2.0 (even reinstalling xplt did not help as pint was not updated).

Present version of pint does not support python 3.8 so I had to remove it from the test workflow.

[eltos]

Thank you, @giadarol

If you don't mind, I'd like to separate the Numpy 2 compatibility change on a separate PR, so we can have xplt 0.9 release pinned with everything numpy<2 and dedicated 0.10 release for numpy>=2

EDIT: See #10

[giadarol]

Thank you @eltos
Thant is perfect for me.
Would you like to make the releases or you prefer that we do?