preflight asked the GitHub release API which version it was upgrading to,
so a host with no internet failed there even with the target binary already
on disk - and `run` never passed its own --target-binary down to preflight,
so supplying one did not help. Read the version from the binary instead
when one is given, and fail if it is not the version the run targets.
Found by the first preflight against the production clone, which is
deliberately cut off from the network.
jcoffey-dev
b786e89b42