Fix API_BASE for dev.html

room_cal/vue/dev.html

@@ -320,8 +320,7 @@
 
   <script>var API_BASE = '';</script>
   <script>
-    const API_BASE = window.API_BASE
-    document.getElementById('base-url').value = API_BASE;
+    document.getElementById('base-url').value = window.API_BASE;
 
     const ACTION_KWARGS = {
       'fetch-feed':   [['feed_name','text','feed name'],['title','text','event title (optional)']],