Work around bug in pint 0.24.0

[khaeru]

Pint 0.24.0 (released 2024-06-) triggered CI failures like this:

FAILED ixmp/tests/report/test_reporter.py::test_platform_units[attrseries] - Failed: Did not log:
    'x: replace units dimensionless with USD/pkm'
among:
    "x: mixed units ['kg', 'USD/pkm'] discarded"
    'x: replace units  with USD/pkm'

This was due to hgrecco/pint#2007 affecting this line:

ixmp/ixmp/report/operator.py

Lines 124 to 126 in 35da509

	log.info(
	f"{name}: replace units {attrs.get('_unit', '(none)')} with {new_unit}"
	)

Work-around / mitigation

• Limit pint to < 0.24.

  At Use pint != 0.24.0 in "pytest" CI workflow #535, with pint 0.23 and NumPy 2.0.0, we see:

  File "/opt/hostedtoolcache/Python/3.12.3/x64/lib/python3.12/site-packages/pint/facets/numpy/numpy_func.py", line 958, in implement_single_dimensionless_argument_func
      func = getattr(np, func_str)
           ^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.12.3/x64/lib/python3.12/site-packages/numpy/__init__.py", line 410, in __getattr__
      raise AttributeError("module {!r} has no attribute "
  AttributeError: module 'numpy' has no attribute 'cumproduct'. Did you mean: 'cumprod'?
  

  This is mentioned at pint 0.24 / numpy 2.0 / python 3.9 issues hgrecco/pint#1974 (comment).

  Because of this (but for no other reason, i.e. no issue inherent to ixmp), the mitigation also requires to limit NumPy < 2.

Fix

• It seems pint 0.24.1 will shortly be released and will reverse the change.
  Wait for the release, confirm the fix, remove the work-around, and close this issue.

[khaeru]

This also affects message-ix-models (see here), so the same work-around could be applied. message_ix is not affected.