[BUG] "unknown revision" when using "path" #987

Is there an existing issue for this?

• I have searched the existing issues

Does this issue exist in the latest version?

• I'm using the latest release

Describe the bug?

I see:

  Error: Unable to locate the previous sha: origin/master
  Error: Please verify that the previous sha is valid, and increase the fetch_depth to a number higher than 50.
  Error: Process completed with exit code 1.

when using this action with `path.

To Reproduce

See this repo PR, with this job.

What OS are you seeing the problem on?

ubuntu-latest or ubuntu-20.04

Expected behavior?

Working action.

Relevant log output

See the job output.

Anything else?

No response

Code of Conduct

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