[v2] Remove adding cache-manifest — think this was replaced by webpack-runtime (#3636)
[v2] Remove adding cache-manifest — think this was replaced by webpack-runtime (#3636)


mingaldrichgan/gatsby,gatsbyjs/gatsby,0x80/gatsby,ChristopherBiscardi/gatsby,gatsbyjs/gatsby,ChristopherBiscardi/gatsby,fk/gatsby,fk/gatsby,gatsbyjs/gatsby,ChristopherBiscardi/gatsby,gatsbyjs/gatsby,mingaldrichgan/gatsby,gatsbyjs/gatsby,0x80/gatsby,gatsbyjs/gatsby,mingaldrichgan/gatsby,ChristopherBiscardi/gatsby,fk/gatsby,0x80/gatsby