Comment 1 for bug 1714405

It appears "number" is the proper type for a floating point value. My use of type: float in config.yaml worked in juju 1.25.6. Perhaps the types changed between versions. Will use "number" for this solution, but more useful expounding upon available types in the upgrade-charm check would be helpful.

Lastly, a number should be acceptable as a string, though I know it's not a strong type-cast, string should be allowed by juju run-action var=<number>.