[pre-commit.ci] auto fixes from pre-commit.com hooks

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Prepare release 7.0.0 (pytest-dev#9598)

* Prepare release version 7.0.0

* Add note to changelog

Co-authored-by: pytest bot <[email protected]>
Co-authored-by: Florian Bruhin <[email protected]>

Add note to changelog

Prepare release version 7.0.0rc1

Fix CHANGELOG header

Prepare release version 6.2.4

Prepare release version 6.2.3

Prepare release version 6.2.2