Update dependency flake8 to v7

This MR contains the following updates:

Package	Type	Update	Change
flake8 (changelog)	dev-dependencies	major	^3.8.2 -> ^7.0.0

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Release Notes

pycqa/flake8

v7.1.1

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v7.1.0

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v7.0.0

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v6.1.0

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v6.0.0

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v5.0.4

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v5.0.3

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v5.0.2

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v5.0.1

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v5.0.0

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v4.0.1

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v4.0.0

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Configuration

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