Update mutations-updates.md (#4424)

Summary:
The mutation variable is `doesLike`, not `doesViewerLike`, which is the name of the returned field.

Pull Request resolved: #4424

Reviewed By: voideanvalue

Differential Revision: D48790909

Pulled By: alunyov

fbshipit-source-id: 016966cf9c942bc6d1f16d7b7d8dfae29dbf33f4

Author: michaelmcneilnet

website/docs/tutorial/mutations-updates.md

@@ -197,7 +197,7 @@ function StoryLikeButton({story}) {
     commitMutation({
       variables: {
         id: data.id,
-        doesViewerLike: !data.doesViewerLike,
+        doesLike: !data.doesViewerLike,
       },
     })
     // end-change