Support for Local Plugin Files in Addition to HTTPS

[jackheuberger]

Is your feature request related to a problem? Please describe.
I'm trying to write a custom Megalinter plugin that's defined in a private repository, meaning a GET request to the .yml definition cannot be made without setting access tokens in request headers.

Describe the solution you'd like
Support for file paths in the PLUGINS property within .mega-linter.yml. For example:

PLUGINS:
  - "<private_repo_submodule>/mega-linter-plugin-xxx/xxx.megalinter-descriptor.yml"

Describe alternatives you've considered
Support for the file:// protocol. For example:

PLUGINS:
  - file://<pwd>/mega-linter-plugin-xxx/xxx.megalinter-descriptor.yml

Additional context
I would be willing to work on this. Thanks!

[nvuillam]

@jackheuberger i'd be glad to accept such PR :)