Fix macos/windows CI

[prisae]

Problem: There is a failure in test_transform.py::test_hankel for MacOS/Windows CI; when using scipy v1.9.0. Not sure what is causing it.

Currently a dirty workaround: In the MacOS/Windows-CI we exclude scipy!=1.9.0. If it will be resolved upstream, good. If not, it will resurface with any new SciPy version.

Also restricting currently flake8<5, due to incompatibility with pytest-flake8.

[coveralls]

Pull Request Test Coverage Report for Build 2788524239

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 99.68%

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Totals
Change from base Build 2785127561:	0.0%
Covered Lines:	3112
Relevant Lines:	3122

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💛 - Coveralls