[release-20.0] Copy `v20.0.0` release notes

[frouioui]

This Pull Request copies the release notes found on release-20.0-rc to keep release notes up-to-date after the v20.0.0 release.

[github-actions[bot]]

This PR is being marked as stale because it has been open for 30 days with no activity. To rectify, you may do any of the following:

• Push additional commits to the associated branch.
• Remove the stale label.
• Add a comment indicating why it is not stale.

If no action is taken within 7 days, this PR will be closed.

[github-actions[bot]]

This PR was closed because it has been stale for 7 days with no activity.