fix(docs): Editing the fine print of contributor-swag (#11332)
fix(docs): Editing the fine print of contributor-swag (#11332)

+ Added mention of free item **per tier** instead of just one free item ** per ** contributor
ChristopherBiscardi/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby,ChristopherBiscardi/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby,ChristopherBiscardi/gatsby,gatsbyjs/gatsby,ChristopherBiscardi/gatsby