lintapp: use HTTPS protocol

Change-Id: Ie8f47a410ab568ebcfb308db1c4fe060e1479614
Reviewed-on: https://go-review.googlesource.com/118576
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
diff --git a/lintapp/assets/templates/index.html b/lintapp/assets/templates/index.html
index 9f3d18f..3066e0f 100644
--- a/lintapp/assets/templates/index.html
+++ b/lintapp/assets/templates/index.html
@@ -7,7 +7,7 @@
 </head>
 <body>
   <h3>Go Lint</h3>
-  <p>Go Lint lints <a href="http://golang.org/">Go</a> source files on GitHub,
+  <p>Go Lint lints <a href="https://golang.org/">Go</a> source files on GitHub,
   Bitbucket and Google Project Hosting using the <a
     href="https://github.com/golang/lint">lint package</a>.
   <form method="POST" action="/-/refresh">