Merge pull request #752 from reactjs/renovate/react-monorepo

Update react monorepo to v16.8.4

Author: Daniel15

src/React.Core/package-lock.json

@@ -12,8 +12,8 @@
     "babel-preset-stage-0": "6.24.1",
     "babel-standalone": "6.26.0",
     "prop-types": "15.7.2",
-    "react": "16.8.3",
-    "react-dom": "16.8.3",
+    "react": "16.8.4",
+    "react-dom": "16.8.4",
     "webpack": "4.29.5",
     "webpack-cli": "3.2.3"
   }