Provide cache-hit output

[dhvcc]

I'd like to propose adding cache-hit output, since this action utilizes actions/cache. This proposal was originally made in actions/setup-python#371, so full justification can be found here (this is for python, but I think it doesn't matter that much?)

[eregon]

Do you have a concrete example how this output would be useful?

From that linked issue:

This would be helpful if, for example, we need add stuff to PATH if this cache was hit.

I don't see how that would apply here. No matter cache hit or not the PATH would be the same.

[dhvcc]

Sure, I'll try to find more ruby-related reasons and get back at you. Thanks for the response!

[dhvcc]

It seems like all use cases for this feature are really covered by this action, closing this