bf luis:application:import and bf luis:version:import do not support LU input

[AndyCW]

Versions

What CLI version are you using. 4.9,1
What Nodejs version are you using
What command-line interpreters are you using pwsh, bash
What OS are you using Windows 10, Linux

Describe the bug

Documentation at https://github.com/microsoft/botframework-cli/tree/master/packages/luis#bf-luisapplicationimport states that this function "Imports LUIS application from JSON or LU content". It does not, it only supports JSON input.

Same problem applies to https://github.com/microsoft/botframework-cli/tree/master/packages/luis#bf-luisversionimport. It states "Imports a new version into a LUIS application from JSON or LU content." Again, it only supports JSON.

To Reproduce

Steps to reproduce the behavior:

1. Supply a .lu file in the --in parameter
2. errors

Expected behavior

It should be able to import a .lu file.

Additional context

Add any other context about the problem here.

[bug]