BUG: pip installation leads to ValueError: Must supply freq for datetime value

[ahobeost]

The installation of the pytrnsys-gui release, as well as the developer installation works correctly.
When only installing pytrnsys-process using pip install, the following error is obtained when running:

fig, ax = api.energy_balance(sim_data.monthly,
                                 q_in_columns=["QSnk60PauxCondSwitch_kW"],
                                 q_out_columns=["QSnk60P", "QSnk60PDhw", "QSnk60dQlossTess", "QSnk60dQ"],
                                 q_imb_column="QSnk60qImbTess"
                                 )

Traceback (most recent call last):
  File "C:\GIT\dev\pytrnsys_process_workshop_2\venv\Lib\site-packages\pytrnsys_process\process\process_batch.py", line 557, in _process_simulation
    scenario(simulation)
  File "C:\GIT\dev\pytrnsys_process_workshop_2\tutorials\01_processing_steps.py", line 56, in energy_balance_tess_monthly
    fig, ax = api.energy_balance(sim_data.monthly,
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\GIT\dev\pytrnsys_process_workshop_2\venv\Lib\site-packages\pytrnsys_process\plot\plot_wrappers.py", line 290, in energy_balance
    return plotter.plot(
           ^^^^^^^^^^^^^
  File "C:\GIT\dev\pytrnsys_process_workshop_2\venv\Lib\site-packages\pytrnsys_process\plot\plotters.py", line 33, in plot
    fig, ax = self._do_plot(df, columns, **kwargs)
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\GIT\dev\pytrnsys_process_workshop_2\venv\Lib\site-packages\pytrnsys_process\plot\plotters.py", line 100, in _do_plot
    ax = df[columns].plot.bar(**plot_kwargs)
         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\GIT\dev\pytrnsys_process_workshop_2\venv\Lib\site-packages\pandas\plotting\_core.py", line 1432, in bar
    return self(kind="bar", x=x, y=y, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\GIT\dev\pytrnsys_process_workshop_2\venv\Lib\site-packages\pandas\plotting\_core.py", line 1185, in __call__
    return plot_backend.plot(data, kind=kind, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\GIT\dev\pytrnsys_process_workshop_2\venv\Lib\site-packages\pandas\plotting\_matplotlib\__init__.py", line 70, in plot
    plot_obj = PLOT_CLASSES[kind](data, **kwargs)
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\GIT\dev\pytrnsys_process_workshop_2\venv\Lib\site-packages\pandas\plotting\_matplotlib\core.py", line 1877, in __init__
    PeriodConverter.convert_from_freq(
  File "C:\GIT\dev\pytrnsys_process_workshop_2\venv\Lib\site-packages\pandas\plotting\_matplotlib\converter.py", line 245, in convert_from_freq
    values = PeriodConverter._convert_1d(values, freq)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\GIT\dev\pytrnsys_process_workshop_2\venv\Lib\site-packages\pandas\plotting\_matplotlib\converter.py", line 273, in _convert_1d
    return [_get_datevalue(x, freq) for x in values]
            ^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\GIT\dev\pytrnsys_process_workshop_2\venv\Lib\site-packages\pandas\plotting\_matplotlib\converter.py", line 281, in _get_datevalue
    return Period(date, freq).ordinal  # pyright: ignore[reportAttributeAccessIssue]
           ^^^^^^^^^^^^^^^^^^
  File "pandas/_libs/tslibs/period.pyx", line 3076, in pandas._libs.tslibs.period.Period.__new__
ValueError: Must supply freq for datetime value

This is likely due to a different version of pandas being used.