fix(starters): update old demo links (#9688)
fix(starters): update old demo links (#9688)

I noticed that a couple of the demo links for starters were returning as not found. The GitHub links were still valid but had different demo links. I updated to reflect the demo links listed on their respective GitHub repository.

0x80/gatsby,ChristopherBiscardi/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby,ChristopherBiscardi/gatsby,ChristopherBiscardi/gatsby,ChristopherBiscardi/gatsby,0x80/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby,0x80/gatsby,gatsbyjs/gatsby