Support for react-helmet v6.0.0

[hrishikesh-k]

I was trying out this starter and updated all my packages in package.json. Thus, I ended up updating react-helment to 6.0.0. Doing this breaks the build. However, I searched on Google and found this: gatsbyjs/gatsby#10578 (comment). The solution is to change Line 2 in src/components/head.js and Line 3 in src/components/seo.js from import Helmet from "react-helmet"; to import { Helmet } from "react-helmet";