chore(list-header): run lint

Author: thetaPC

core/src/components/list-header/test/basic/index.html

@@ -84,7 +84,7 @@
 
     <style>
       ion-content {
-        --background: #F1F1F1;
+        --background: #f1f1f1;
       }
     </style>
   </body>