The script used to identify and update the change is added into the GitHub
workflows script directory. A workflow action can be created to trigger the
script to update the headers on the first of every new year. Possibly a task for
a consequent PR.
- Moved backend determination to `config.el`
- Replaced unnecessary backquote construct with simple quotation
- Replaced `pcase` form with only one-arm with `when` or `unless` form
