Update copyright year (#573)

Author: github-actions[bot]

README.md

@@ -209,7 +209,7 @@ preserved and does not require housekeeping.
 
 [![License](https://img.shields.io/github/license/cylc/cylc-doc.svg?color=lightgrey)](https://github.com/cylc/cylc-doc/blob/master/LICENSE)
 
-Copyright (C) 2008-<span actions:bind='current-year'>2022</span> NIWA & British Crown (Met Office) & Contributors.
+Copyright (C) 2008-<span actions:bind='current-year'>2023</span> NIWA & British Crown (Met Office) & Contributors.
 
 Cylc is free software: you can redistribute it and/or modify it under the terms
 of the GNU General Public License as published by the Free Software Foundation,

src/conf.py

@@ -94,7 +94,7 @@
 
 # General information about the project.
 project = 'Cylc'
-__copyright_year = 2022  # NOTE: this is automatically set by GH Actions
+__copyright_year = 2023  # NOTE: this is automatically set by GH Actions
 copyright = (
     f'2008-{__copyright_year} NIWA & British Crown (Met Office) & Contributors'
 )