Remove horizontal padding for pill items

This gives the contents of each item more space
which is useful on smaller screens or at higher
zoom levels.

Each item still has a 2px border so is prevented
from its contents touching those of the other
items. They are also flex-items, set to occupy a
quarter of the available space so will removing
this padding will not effect their width.

app/assets/stylesheets/components/pill.scss

@@ -31,7 +31,7 @@
     float: left;
     box-sizing: border-box;
     width: 100%;
-    padding: 10px;
+    padding: 10px 0px;
   }
 
   a {