fix(package): update react-dom to version 16.12.0

Closes #61

Author: greenkeeper[bot]

package.json

@@ -16,7 +16,7 @@
     "memoize-one": "^4.0.0",
     "prop-types": "^15.6.0",
     "react": "16.12.0",
-    "react-dom": "16.6.3",
+    "react-dom": "16.12.0",
     "react-virtualized": "^9.20.1"
   },
   "devDependencies": {