chore(package): update react-modal to version 3.9.1

Author: greenkeeper[bot]

package.json

@@ -91,7 +91,7 @@
     "react-draggable": "3.0.5",
     "react-ga": "2.5.3",
     "react-intl": "2.9.0",
-    "react-modal": "3.6.1",
+    "react-modal": "3.9.1",
     "react-popover": "0.5.10",
     "react-redux": "5.0.7",
     "react-responsive": "5.0.0",