tap package create: Cannot resolve OpenTap dependency if manually specified and not running from the OpenTAP folder

If you have a package that specifies the dependency manually:

 <Dependencies>
    <PackageDependency Package="OpenTAP"/>
  </Dependencies>

and that package XML file is not referencing any .NET DLLs, but just collects arbitrary files from the git folder, then the package process fails with the following error message:

00:00:00.568 : tap           : Error       : Package dependency 'OpenTAP' specified in package definition is not installed. Please install a compatible version first.

This can be reproduced by building the attached project files and the doing bin/Debug/tap.exe package create package.xml.

TapBuildTest.zip

Removing the PackageDependency fixes the issue, but the behavior is a bit surprising.