Use https for logo (#46)

Using an HTTP URL for this image causes unfriendly mixed-content warnings in modern browsers

Author: ian-r-rose

index.html

@@ -526,7 +526,7 @@ <h2 id="supported-by"><a href="#supported-by" class="link-unstyled">Supported By
                   <a href="https://anaconda.com"><img src="https://upload.wikimedia.org/wikipedia/en/c/cd/Anaconda_Logo.png"></a>
                 </div>
                 <div class="col supporter">
-                  <a href="https://www.capitalone.com/"><img src="http://www.capitalone.co.uk/images/c1/brand/logo.svg"></a>
+                  <a href="https://www.capitalone.com/"><img src="https://www.capitalone.co.uk/images/c1/brand/logo.svg"></a>
                 </div>
                 <div class="col supporter">
                   <a href="https://coiled.io/"><img src="https://raw.githubusercontent.com/coiled/logos/master/horizontal.svg"></a>