Update dependency react-helmet to v6

Author: renovate-bot

src/React.Template/reactnet-webpack/package-lock.json

@@ -12,7 +12,7 @@
     "react": "^16.8.2",
     "react-dom": "^16.8.2",
     "react-emotion": "^9.2.12",
-    "react-helmet": "^5.2.0",
+    "react-helmet": "^6.0.0",
     "react-jss": "^8.6.1",
     "react-router-dom": "^5.0.0",
     "react-select": "^3.0.4",