chore: correct homepage

Author: ascorbic

package.json

@@ -42,7 +42,7 @@
     "prettier": "^2.3.2",
     "typescript": "^4.3.5"
   },
-  "homepage": "https://github.com/gatsbyjs/gatsby/tree/master/packages/gatsby-plugin-netlify#readme",
+  "homepage": "https://github.com/netlify/gatsby-plugin-netlify#readme",
   "keywords": [
     "gatsby",
     "gatsby-plugin",