[v2] Update using-jss example (#5832)
[v2] Update using-jss example (#5832)

* Bump package versions

* Add react react-dom react-jss

* Flag version 2.0.0

* Revert version

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