Add support for credentials for private git repo dependencies

[allen-servedio]

Dependencies allows you to define a location and version of the artifact that you want to use. Here is an example:

project:
  name: MyProject
  version: 0.0.1
  packages:
    mypackage:
      license: Apache-2.0
      version: 0.0.1
      dependencies:
        mydep:
          location: https://github.com/my-org/my-private-repo
          version: 0.0.1

However, there does not appear to be a way to define credentials for accessing this repository - which is required for private repos.

The error you get when you try to do this is also not great (it is calling: https://github.com/my-org/my-private-repo/zipball/0.0.1):

Error: manifestreader.go [103]: [ERROR_YAML_FILE_FORMAT_ERROR]: File: [manifest.yaml]:
==> manifestreader.go [147]: [ERROR_YAML_FILE_FORMAT_ERROR]: File: [mypackage]:
==> ==> zip: not a valid zip file
==>

What is actually happening is the call results in a 404 from github.

[allen-servedio]

At a suggestion from @csantanapr , I tried to add a username + API token to the repo URL. Unfortunately the code to check if it is a github location does not account for this and so you get this error:

Error: manifestreader.go [73]: [ERROR_YAML_FILE_FORMAT_ERROR]: File: [manifest.yaml]:
==> Dependency type is unknown.  wskdeploy only supports /whisk.system bindings or github.com packages.
==>

That, actually, looks easy to fix...

[allen-servedio]

Further, this should allow valid urls such as https://username:password@example.com. This includes alternate hosts such as: gitlab.com or github.ibm.com (there certainly could be more).

[allen-servedio]

Where can we add the docs for this fix?