Typo reported by Adam Braimbridge, thanks

source/index.html

@@ -16,7 +16,7 @@ suppress_header: true
           </p>
           <div class="landing-button">
-            <a href="/subscription" class="btn btn-success btn-lg action-button">Get a subsciption for GitLab</a>
+            <a href="/subscription" class="btn btn-success btn-lg action-button">Get a subscription for GitLab</a>
           </div>
         </div>