[Feature] Add support for checkout path

[IvanPizhenko]

Is your feature request related to a problem? Please describe.

I am checking out multiple repositories like this:

      - name: Checkout this repo
        uses: actions/checkout@v2
        with:
          path: this
          fetch-depth: 2

      - name: Checkout another repo
        uses: actions/checkout@v2
        with:
          repository: SomeAccount/AnotherRepo
          path: another
          fetch-depth: 2

But this action only works for default checkout path.

Describe the solution you'd like?

Like this:

      - name: Get changed files from this repo
        id: changed-files-this
        uses: tj-actions/changed-files@v1.x.y
        with:
          #  Same path as in the "checkout" action
          path: this

      - name: Get changed files from another repo
        id: changed-files-another
        uses: tj-actions/changed-files@v1.x.y
        with:
          #  Same path as in the "checkout" action
          path: another

Describe alternatives you've considered?

No response

Anything else?

No response

Code of Conduct

• I agree to follow this project's Code of Conduct

[github-actions]

Thanks for reporting this issue.

[IvanPizhenko]

Edited description. Please read last version.

[IvanPizhenko]

Submitted PR for this. Please review.