Add input to change directory

[AlexDCraig]

It would be helpful to cover the case where a user checks out the repo, but to a non-traditional location. For example, suppose:

    - name: Check Out
      uses: actions/checkout@v2
      with:
        path: .source

It would be nice to run the action like so:

    - name: Apply Tag of Commit Hash to Master
      uses: mathieudutour/[email protected]
      with:
        path: .source

[AlexDCraig]

I believe this could be resolved with this: https://github.com/mathieudutour/github-tag-action/pull/100