message: Update siteConfig.js
  Now that we have a Docs tab on backstage.io, seems like the GitHub menu item can go back to linking to the top of the repo.
diff: @@ -35,7 +35,7 @@ const siteConfig = {
  // For no header links in the top nav bar -> headerLinks: [],
  headerLinks: [
  {
  - href: 'https://github.com/spotify/backstage#backstage',
  + href: 'https://github.com/spotify/backstage',
  label: 'GitHub',
  },
  {
  