upgrade to downshift@4

package.json

@@ -28,7 +28,7 @@
     "codemirror-solidity": "^0.2.1",
     "date-fns": "^2.9.0",
     "dom-to-image": "^2.6.0",
-    "downshift": "^3.4.7",
+    "downshift": "^4.0.4",
     "dropperx": "^1.0.1",
     "eitherx": "^1.0.2",
     "escape-goat": "^2.1.1",

yarn.lock

@@ -3808,10 +3808,10 @@ dot-prop@^5.0.0:
   dependencies:
     is-obj "^2.0.0"
 
-downshift@^3.4.7:
-  version "3.4.7"
-  resolved "https://registry.yarnpkg.com/downshift/-/downshift-3.4.7.tgz#f8910fee736f10f11920715c26e6c3211da4cf6b"
-  integrity sha512-Nkig2NenS+BlwpA+gFlUCYfR5HyUFyxitmkISilNzvfLfGV1lYSKaUnAQ9aBegqXm3XmavGd9sxV5Ly7fBhSQg==
+downshift@^4.0.4:
+  version "4.0.4"
+  resolved "https://registry.yarnpkg.com/downshift/-/downshift-4.0.4.tgz#d7e44799563dd488d737a56ebb56237ea79bdc63"
+  integrity sha512-NIwOW2DE+JOu6EQuIa/lmnS7ParIyII/qkk95QUb6DE4g7OEyyI8GKkLFQaIisJIHfLQyVNhCnzzqeWUKSmutA==
   dependencies:
     "@babel/runtime" "^7.4.5"
     compute-scroll-into-view "^1.0.9"