Testing with Python 3.11 and support it

[WenjieDu]

What does this PR do?

Fixing #245

Before submitting

• This PR is made to fix a typo or improve the docs (you can dismiss the other checks if this is the case).
• Was this discussed/approved via a GitHub issue? Please add a link to it if that's the case.
• I have commented my code, particularly in hard-to-understand areas.
• I have written necessary tests and already run them locally.

[coveralls]

Pull Request Test Coverage Report for Build 6990032033

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage decreased (-0.02%) to 83.424%

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Files with Coverage Reduction	New Missed Lines	%
pypots/classification/base.py	1	74.07%

Totals
Change from base Build 6975814042:	-0.02%
Covered Lines:	4439
Relevant Lines:	5321

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💛 - Coveralls