Update dependency styled-components to v4 (reactjs#745)

Author: renovate[bot]

src/React.Sample.Webpack.CoreMvc/package-lock.json

@@ -16,7 +16,7 @@
     "react-jss": "^8.6.1",
     "react-router-dom": "^5.0.0",
     "reactstrap": "^8.0.0",
-    "styled-components": "^3.4.5"
+    "styled-components": "^4.0.0"
   },
   "devDependencies": {
     "@babel/core": "7.4.4",