`pnpm self-update` resolves semver ranges to a specific version, so
`devEngines.packageManager.version: ">=10 <11"` can also go through
the self-update path. That makes readTargetVersion total — it always
returns a string or throws — so the runtime auto-switch fallback (and
the `pnpm_config_pm_on_fail=download` export from #252) is no longer
reachable and gets removed.
Adds a range case to the cache_store_path matrix.