Bump cross-spawn, gatsby, gatsby-plugin-graphql-codegen, gatsby-plugin-postcss, gatsby-plugin-react-helmet, gatsby-plugin-sitemap, gatsby-plugin-typescript, gatsby-remark-autolink-headers, gatsby-remark-copy-linked-files, gatsby-source-filesystem and gatsby-transformer-remark

Bump cross-spawn, gatsby, gatsby-plugin-graphql-codegen, gatsby-plugin-postcss, gatsby-plugin-react-helmet, gatsby-plugin-sitemap, gatsby-plugin-typescript, gatsby-remark-autolink-headers, gatsby-remark-copy-linked-files, gatsby-source-filesystem and gatsby-transformer-remark #3260