Adding Spacetime site to showcase sites.yml (#6265)
Adding Spacetime site to showcase sites.yml (#6265)

* Adding Spacetime site to showcase sites.yml

* Set default featured flag

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