add: initial support for banner to latest version

Author: fbeneventi

docs/overrides/main.html

@@ -3,6 +3,14 @@
   -#}
   {% extends "base.html" %}
 
+  {% block outdated %}
+  You're not viewing the latest version.
+  <a href="{{ '../' ~ 'latest' }}">
+    <strong>Click here to go to latest.</strong>
+  </a>
+  {% endblock %}
+
+
   <!-- Custom front matter -->
   {% block extrahead %}
 
@@ -43,7 +51,7 @@
 
   {% endblock %}
 
-
+ 
 
   <!-- Content -->
   {% block content %}

mkdocs.yml

@@ -71,3 +71,4 @@ extra:
   version:
     provider: mike
     alias: true
+    default: latest