[RFE] Support downgrade graphs

[ecordell]

Feature Request

Is your feature request related to a problem? Please describe.
If an operator gets updated to a particular version, there is no way to downgrade.

Describe the solution you'd like

A general downgrade procedure may be unsafe (how will an operator consumer know if downgrade is safe to attempt?)

But if there were a way to add downgrade edges, in a similar way to upgrade edges, an operator author could provide a supported downgrade path when they believe it to be safe.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.