error: could not find the commit 7566a6a7c279cd6e73ac35ca96a9260de7441f36 in https://github.com/apple/swift-argument-parser
error: ExitCode(rawValue: 1)
the newer commits for some reason do not contain the async API anymore, even though they are still in the async branch (?). what happened?
error: protocol 'AsyncMain' does not exist in module 'ArgumentParser'
import protocol ArgumentParser.AsyncMain
We are working on getting the async branch into main properly. It's likely that a force push to that branch is what caused the commit you reference to be missing.
It can be a good idea to maintain your own fork of dependencies for this reason. If you have a machine with the commit you were using you can always tag it and push it to your own fork to avoid destabilizing things.