Include Python 3.11 to setuptools classifiers

[jumbosushi]

What type of PR is this?

/kind feature

What this PR does / why we need it:

We added Python 3.11 to test workflows with #2003 , but not in setuptools classifiers. This PR updates setup.py

Which issue(s) this PR fixes:

Fixes #1977

Special notes for your reviewer:

Does this PR introduce a user-facing change?

NONE

Additional documentation e.g., KEPs (Kubernetes Enhancement Proposals), usage docs, etc.:

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[roycaihw]

/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: jumbosushi, roycaihw

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