Update documentation w.r.t. publish command option 'pathorURL'

[sanjacob]

the documentation here states:

pathOrUrl The root directory path where the project file is, or a public URL that points to a PWA.

However, in my testing, the command failed unless I specifically pointed the argument to the .msixupload / .msix file.

[sanjacob]

I understand this is usually for directories which include an AppXManifest.xml. However, it would be nice to have this explicitly mentioned as a use case.