Use SSL URLs in mkdocs config

Author: weierophinney

mkdocs.yml

@@ -8,4 +8,4 @@ pages:
 site_name: Expressive Authorization middleware
 site_description: 'Authorization middleware for Expressive and PSR-7 applications'
 repo_url: 'https://github.com/zendframework/zend-expressive-authorization'
-copyright: 'Copyright (c) 2017-2018 <a href="http://www.zend.com/">Zend Technologies USA Inc.</a>'
+copyright: 'Copyright (c) 2017-2018 <a href="https://www.zend.com/">Zend Technologies USA Inc.</a>'