adding author ID as a variable

[norcross]

Description of the Change

This PR is a small change that adds an additional argument for the author ID ($author_id) to the srm_create_redirect function. currently, the author ID is hard-coded to a value of 1, whether or not that author exists at all. when a redirect is created via the admin UI, the current user ID is used as the author ID, so i'd like to also be able to set the author (current or otherwise) when using this function outside of the plugin. the function sets the default to 1, so this would not impact any current implementations.

How to test the Change

1. Pass an ID as the last argument to srm_create_redirect with a default value of 1
2. View the author ID stored in the database

Changelog Entry

Added - New feature
adding additional variable for author ID

Credits

Props @norcross

Checklist:

• I agree to follow this project's Code of Conduct.
• I have updated the documentation accordingly.
• I have added Critical Flows, Test Cases, and/or End-to-End Tests to cover my change.
• All new and existing tests pass.