[load_csv] 'DataFrame' object has no attribute 'append'. Pandas 2.0+ removed "df.append()" function.

[Ilirmc]

Describe the bug
The bw.load_csv function fails to load csvs from a folder, as the pandas "df.append()" function has been removed in pandas 2.0+. This should be replaced with concat.

To Reproduce
df = bw.load_csv(folder_path_containing_csvs)
AttributeError: 'DataFrame' object has no attribute 'append'

Expected behavior
bw.load_csv() should load all the csv files from the folder and return them as a single DataFrame

[stephenholleran]

Thanks @Ilirmc for highlighting. Do you want to suggest a solution or we can take a look at it ourselves?

Cheers,

cc @BiancaMorandi

[stephenholleran]

@Ilirmc are you able to tackle this in the next week or so?
Thanks.