chore(example): update styled-components to v5 (#23259)

Author: mottox2

examples/using-styled-components/package.json

@@ -10,13 +10,13 @@
     "gatsby-plugin-google-analytics": "^2.0.10",
     "gatsby-plugin-offline": "^2.0.21",
     "gatsby-plugin-react-helmet": "^3.0.5",
-    "gatsby-plugin-styled-components": "^3.0.4",
+    "gatsby-plugin-styled-components": "^3.2.3",
     "lodash": "^4.17.14",
-    "react": "^16.7.0",
-    "react-dom": "^16.7.0",
+    "react": "^16.13.1",
+    "react-dom": "^16.13.1",
     "react-helmet": "^5.2.0",
     "slash": "^2.0.0",
-    "styled-components": "^4.1.3"
+    "styled-components": "^5.1.0"
   },
   "keywords": [
     "gatsby"