[code-infra] Improve release merge freeze process

[oliviertassinari]

Summary

Today's release process is documented in https://www.notion.so/mui-org/React-releases-7490ef9581b4447ebdbf86b13164272d?pvs=4#f5cd3164e19e4abcad9366ff7fc101be

We start by creating a changelog and version number, before actually releasing the changes.
With more scale, it feels like it starts to make sense to drop the requirement of having the CHANGELOG.md in the npm package, e.g. https://unpkg.com/browse/@base-ui-components/react@1.0.0-alpha.4/ I don't see it there.

With this constraint gone, we could:

1. Remove the CHANGELOG.md, it won't be accurate anymore.
2. Setup https://mergefreeze.com/
3. Take https://github.com/mui/material-ui/blob/HEAD/scripts/README.md#release.
4. Start with Prepare.3 and Prepare.4. Have people open an PR with it, enable merge freeze until merged
5. Resume from the other steps, making sure that release are done from the commit checkpoint done in 4.

Examples

No response

Motivation

No response

Search keywords: -