[BUG] frame.append is deprecated

[daviddavo]

Description

Using the append method of a pandas dataframe or series is deprecated.

• https://pandas.pydata.org/docs/whatsnew/v1.4.0.html#whatsnew-140-deprecations-frame-series-append

In which platform does it happen?

Python >= 3.9

How do we replicate the issue?

Use any method that uses append in a 3.9 environment and it will raise a FutureWarning

Expected behavior (i.e. solution)

No warning raised

Other Comments

Changing all the appends to concats is a straightforward task, it would be a good first issue. It would also be a step forward into #1919

[miguelgfierro]

@daviddavo is this fixed?

[daviddavo]

Yeah, it should be fixed with #2058