Feature/alt metadata json repo

[jcuna]

Alternate repo for hosting json and fix to inputs.path

• Allows for use of alternative repo to host shields.json. Useful for running an action in a private repo while pushing shields.json to a public repo where it can be properly referenced.
• Attempts to fix inputs.path not properly working for nested paths. i.e. directory/subfile.json.
• Updates readme with instructions on new options

Attempts to fix... while I tested non server script work, I obviously have not tested it in your server. So please be mindful to test before publishing it.

[RubbaBoy]

This looks great, thanks for your contribution! I just left for vacation so I won't be available for about a week, but once I'm back at my computer I'll do a deeper review/testing on the server.

[RubbaBoy]

Just pushed the updates to the server, your changes should be reflected

[jcuna]

Just tested having deep directories path and it works. Thanks for merging my PR, we're going to be using this action extensively.

[RubbaBoy]

Awesome, glad to hear it! If you have any other suggestions at all of features/whatnot feel free to make an issue, I'd like to work on this a bit more in the future.