[Feature] command to promote dev plugins to semver

[mrcjkb]

Sometimes plugins that previously only existed as dev plugins are published with semver releases later on (e.g. the tree-sitter parsers).
Currently, users have to manually switch from dev to semver and there's no indication that this is possible.

Rocks update doesn't promote dev plugins to semver.
It would be nice if there were an option to do this, e.g. :Rocks[!] promote {rock?} command (with completions for rocks that can be promoted).
Or, alternately, a prompt in :Rocks[!] update (or both).

Suggestions for a better name than promote are more than welcome!