use dynamic date(year) for copyright instead of hardcoded

Author: Kukurijek

mkdocs.yml

@@ -3,7 +3,6 @@ site_name: fastlane docs
 site_author: fastlane team
 site_description: Documentation for fastlane tools, the easiest way to automate building
   and releasing your iOS and Android apps
-copyright: Copyright &copy; 2021 <a href="https://fastlane.tools">fastlane</a>
 repo_url: https://github.com/fastlane/docs
 theme:
   name: readthedocs

theme/footer.html

@@ -22,7 +22,7 @@
     </p>
   </div>
 
-  Built with <a href="http://www.mkdocs.org">MkDocs</a> using a <a href="https://github.com/readthedocs/sphinx_rtd_theme">theme</a> provided by <a href="https://readthedocs.org">Read the Docs</a> - {{ config.copyright }}
+  Built with <a href="http://www.mkdocs.org">MkDocs</a> using a <a href="https://github.com/readthedocs/sphinx_rtd_theme">theme</a> provided by <a href="https://readthedocs.org">Read the Docs</a> - Copyright &copy; {{ build_date_utc.strftime('%Y') }} <a href="https://fastlane.tools">fastlane</a>
 </footer>
 
 <script type="text/javascript">