Bug#1074629: pyswarms: fails tests with matplotlib 3.8

[Drew Parsons]

Source: pyswarms
Version: 1.3.0-6
Severity: normal

pyswarms is failing tests with matplotlib 3.8 from experimental:

 57s ____________ ERROR collecting tests/utils/plotters/test_plotters.py ____________
 57s ImportError while importing test module '/tmp/autopkgtest-lxc.ljy3li2v/downtmp/autopkgtest_tmp/python3.11/tests/utils/plotters/test_plotters.py'.
 57s Hint: make sure your test modules/packages have valid Python names.
 57s Traceback:
 57s /usr/lib/python3.11/importlib/__init__.py:126: in import_module
 57s     return _bootstrap._gcd_import(name[level:], package, level)
 57s tests/utils/plotters/test_plotters.py:17: in <module>
 57s     from matplotlib.axes._subplots import SubplotBase
 57s E   ModuleNotFoundError: No module named 'matplotlib.axes._subplots'
 57s ------------------------------- Captured stdout --------------------------------
 57s No display found. Using non-interactive Agg backend.
 57s ------------------------------- Captured stderr --------------------------------
 57s 2024-07-01 02:27:00,130 - matplotlib.font_manager - INFO - generated new fontManager
 57s =========================== short test summary info ============================
 57s ERROR tests/utils/plotters/test_plotters.py
 57s !!!!!!!!!!!!!!!!!!!! Interrupted: 1 error during collection !!!!!!!!!!!!!!!!!!!!
 57s =============================== 1 error in 1.46s ===============================