Revert a major instance upgrade.
edgedb instance revert [options] name
When edgedb instance upgrade performs a major version
upgrade on an instance the old instance data is kept around. The
edgedb instance revert command removes the new instance version and
replaces it with the old copy. It also ensures that the previous
version of EdgeDB server is used to run it.
The name of the EdgeDB instance to revert.
Do not check if upgrade is in progress.
Do not ask for a confirmation.