Bump major version to v4.0.0

[github-actions[bot]]

Description

Ready to be merged into main branch, at the discretion of the maintainers, to bump the major part of the version number.

To bump version to v4.0.0

1. click Ready for review button below, to get this PR out of Draft mode
2. click Rebase and merge button below

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Workflow metadata

Auto-generated on run #3014382314 by version-increments job from changelog.yaml workflow.