Use utterances for comments on second edition posts

blog/templates/second-edition/page.html

@@ -39,11 +39,14 @@
     </div>
 
     <hr>
-    <script data-isso="//comments.phil-opp.com/fcgi-bin/isso"
-        src="//comments.phil-opp.com/fcgi-bin/isso/js/embed.min.js"></script>
     <section>
         <h2>Comments</h2>
-        <section id="isso-thread"></section>
+        <script src="https://utteranc.es/client.js"
+            repo="phil-opp/blog_os"
+            branch="master"
+            issue-term="pathname"
+            async>
+        </script>
     </section>
 
 {% endblock after_main %}