Add support for `working-directory` arg in connect-publish action

[meatballhat]

so that a base directory other than the current working directory may be used when resolving entries in the dir argument. The name working-directory was chosen based on the same name used for the builtin run step in github actions.

ref: https://docs.github.com/en/actions/using-workflows/workflow-syntax-for-github-actions#jobsjob_iddefaultsrun

[aronatkins]

Also related is the top-level defaults.run: https://docs.github.com/en/actions/using-workflows/workflow-syntax-for-github-actions#defaultsrun