Featured Medium post should be most recent post (#366)

* #365 - on load, fetch latest medium posts and display on landing page

* refactor to remove jq dependency

* handle fallback link text

themes/tracer/layouts/partials/home/cncf.html

@@ -4,3 +4,4 @@
     <img src="/img/cncf-logo.png" alt="">
   </div>
 </section>
+

themes/tracer/layouts/partials/home/hero.html

@@ -16,10 +16,23 @@ <h2 class="dark-blue">Libraries available in {{ len $languages }} languages</h2>
         </p>
       </div>
       {{- with $hero.update -}}
-      <div class="update">
-        <a href="{{ .url }}" target="_blank">
-          {{ .title }}
+      <h4>The latest from our blog:</h4>
+      <div id="update" class="update">
+        <a href="" target="_blank">
         </a>
+        <script type="text/javascript">
+          fetch('https://api.rss2json.com/v1/api.json?rss_url=https%3A%2F%2Fmedium.com%2Ffeed%2Fopentracing')
+            .then(function(res) {
+              res.json().then(function(data) {
+                let item = data.items[0];
+                let content = `<a href="${item.link}" target="_blank">${item.title}</a>`;
+                document.getElementById('update').innerHTML = content;
+              });
+            }).catch(function() {
+              let content = `<a href="https://medium.com/opentracing" target="_blank">OpenTracing on Medium</a>`
+              document.getElementById('update').innerHTML = content;
+            });
+      </script>
       </div>
       {{- end -}}
     </section>