GitHubDesktop.munki: remove minimum_os_version from Input
GitHubDesktop.munki: remove minimum_os_version from Input

- not needed as MunkiImporter (invoking makepkginfo) will automatically set the appropriate
  `minimum_os_version` key based on the app's Info.plist
autopkg/homebysix-recipes,autopkg/homebysix-recipes,autopkg/homebysix-recipes