Support running action within a sub-directory

[petemounce]

yor has a requirement on actions/checkout having a fetch-depth: 0 so it can obtain the git history it needs.

This is more expensive to fetch for large repositories.

It would be handy to be able to supply working-directory to the action so that it can happen within its own managed-specifically-for-the-action clone.

Currently, the action fails I think because the command's working-directory is the workspace path, and if a checkout is done into somewhere else (and then --directory is specified to aim there), the git switch done up-front in run() fails with no possibility to adjust where it's run from.

/usr/bin/git switch pete/yor
fatal: not a git repository (or any of the parent directories): .git

/home/runner/work/_actions/some-org/gcp-terraform-workflows/pete/yor/.github/actions/yor-action/node_modules/@actions/exec/lib/toolrunner.js:592
                error = new Error(`The process '${this.toolPath}' failed with exit code ${this.processExitCode}`);
^
Error: The process '/usr/bin/git' failed with exit code 128
    at ExecState._setResult (/home/runner/work/_actions/some-org/gcp-terraform-workflows/pete/yor/.github/actions/yor-action/node_modules/@actions/exec/lib/toolrunner.js:592:1)
    at ExecState.CheckComplete (/home/runner/work/_actions/some-org/gcp-terraform-workflows/pete/yor/.github/actions/yor-action/node_modules/@actions/exec/lib/toolrunner.js:575:1)
    at ChildProcess.<anonymous> (/home/runner/work/_actions/some-org/gcp-terraform-workflows/pete/yor/.github/actions/yor-action/node_modules/@actions/exec/lib/toolrunner.js:469:1)
    at ChildProcess.emit (node:events:524:28)
    at maybeClose (node:internal/child_process:1104:16)
    at Socket.<anonymous> (node:internal/child_process:456:11)
    at Socket.emit (node:events:524:28)
    at Pipe.<anonymous> (node:net:343:12)

If this

  await exec.exec(`git switch ${githubRef}`)

became

  await exec.exec(`git -C "${workingDirectory}" switch ${githubRef}`)

that could work.

However, I have not inspected the action's code to know whether that would be the only place necessary to touch for this. It might be more expedient to change the cwd once as the first thing.