Self-update corepack according to version range in package.json

[haines]

Trying to get all our developers and CI processes to update corepack manually due to #612 is quite painful. It would be nice if corepack had a self-update feature whereby the version of corepack itself could be specified in package.json as well as the package manager version.

Or alternatively if a self-update is not desirable, if we could at least put a constraint like "engines": {"corepack": ">= 0.31.0"} and have corepack exit with an error if that is not met, then that would at least prompt folks to update it themselves.