Merge pull request #314 from ifours/patch-1

Update UPGRADE.md

Author: dapi

UPGRADE.md

@@ -91,7 +91,7 @@ Use
 ```javascript
 const components = {
   AddCardLink:      () => <button>New Card</button>,
-  CustomLaneHeader: CustomLaneHeader,
+  LaneHeader:       CustomLaneHeader,
   NewCardForm:      NewCard,
   NewLaneSection:   NewLane,
   Card:             CustomCard