use go get

Other languages have installer line, go packages are installed with "go get" command.

Author: cenkalti

html/index.html

@@ -461,7 +461,7 @@ <h3 class="panel-title">Go</h3>
 
             <div class="panel-footer">
               <div>
-                <code>import "github.com/dgrijalva/jwt-go"</code>
+                <code>go get github.com/dgrijalva/jwt-go</code>
               </div>
 
             </div>