Pin pandas yet again avoid new 2.2.1 as well

[valeriupredoi]

Description

Closes #2349

As @schlunma correctly points out in the issue, Pandas have not fixed a bug in 2.2.1 either, bug nicely described by Manu in #2305 (original PR with first pin):

This PR fixes recent test failures that are caused by a bug in pandas. This bug breaks the round function that we use to round to the nearest second:

ESMValCore/esmvalcore/cmor/_fixes/icon/icon.py

Lines 495 to 497 in d6008f3

	new_datetimes = (year_month_day + day_float).round(
	'S'
	).dt.to_pydatetime()

In addition, this removes the use of two deprecated features:

1. Replace 'S' by 's' (see https://pandas.pydata.org/pandas-docs/stable/user_guide/timeseries.html#offset-aliases)
2. Surround DatetimeProperties.to_pydatetime by np.array as recommended in the deprecation message. Unfortunately, this does not remove the warning, but hopefully this will avoid problems in the future.

Link to documentation:

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Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 94.11%. Comparing base (c9a5982) to head (c540c68).

❗ Current head c540c68 differs from pull request most recent head 7d6d3c7. Consider uploading reports for the commit 7d6d3c7 to get more accurate results

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2353   +/-   ##
=======================================
  Coverage   94.11%   94.11%           
=======================================
  Files         241      241           
  Lines       13381    13381           
=======================================
  Hits        12594    12594           
  Misses        787      787           

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[schlunma]

Thanks V!

[valeriupredoi]

Cheers Manu 🍺