release:dsh takes major, minor, patch, or an explicit version and writes one
version across the family; release:vendor takes none and increments each
package's own patch, but only for packages whose published payload changed since
their vendor-<package>-v* tag. That tag is the record of the commit a package
last published from, so the change judgement needs no state file, and the diff
is filtered through the manifest's files rules - editing a vendored comment does
not trigger a release.
Both refresh the lockfile, commit, and print the tag to create after the commit
merges. --dry-run reports the plan and writes nothing.
Incrementing the release numbers is also what drops an upstream prerelease
segment: cordis 4.0.0-rc.7 publishes as 4.0.1, because a prerelease version
would not satisfy a consumer's plain range.