Fixed recursive flag stat error

[alexyz79]

Description of your changes

Changed the behaviour of 'findSubmodules' in 'internal/cli/run.go', by returning an empty module list if the folder is not found, this will allow the normal execution of terraform-docs using '--recursive' even if the 'modules' folder is not available. It fixes when the recursive flag is used on a project without a "modules" folder.

It only returns an empty list if 'err' is a 'NotExist' error, other wise it keeps the same behaviour: returns the error code.

Fixes #654

I have:

• Read and followed terraform-docs' contribution process.
• All tests pass when I run make test.

How has this code been tested

Tested in terraform projects with and without "modules" folder.

[trenslow]

any updates on getting this merged?

@khos2ow

[khos2ow]

The fix looks good and simple enough, but I don't see the benefit of it. This error, if happens, indicates either of two things: 1) you do intend for the modules folder to be there, but it's not (missing, typo in folder name, etc) 2) you do not intend for the recursive modules to be there, hence the .terraform-docs.yml or the command line execution flags are not supposed to have the recursive configs.

In both cases the error seems to be needed, IMO.