[release] v6.18.1

[michelengelen]

• I have followed (at least) the PR section of the contributing guide.

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The following steps must be proposed as a pull request.

• Compare the last tag with the branch upon which you want to release (next for the alpha / beta releases and master for the current stable version).
• Clean the generated changelog, to match the format of https://github.com/mui/mui-x/releases.
• Update the root package.json's version
• Update the versions of the other package.json files and of the dependencies with yarn release:version (yarn release:version prerelease for alpha / beta releases).
• Open PR with changes and wait for review and green CI.
• Merge PR once CI is green, and it has been approved.

Release the packages

• Checkout the last version of the working branch
• Make sure you have the latest dependencies installed: yarn.
• Build the packages: yarn release:build.
• Release the versions on npm: yarn release:publish (you need your 2FA device).
• Push the newly created tag: yarn release:tag.

Publish the documentation

The documentation must be updated on the docs-vX branch (docs-v4 for v4.X releases, docs-v5 for v5.X releases, ...)

• Push the working branch on the documentation release branch to deploy the documentation with the latest changes.

Publish GitHub release

• After documentation is deployed, publish a new release on GitHub releases page

[mui-bot]

Deploy preview: https://deploy-preview-10960--material-ui-x.netlify.app/

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