Adds support for Mailchimp Group fields

Author: benjaminhoffman

examples/gatsby-v2/package.json

@@ -5,7 +5,7 @@
   "author": "Kyle Mathews <mathews.kyle@gmail.com>",
   "dependencies": {
     "gatsby": "next",
-    "gatsby-plugin-mailchimp": "^5.1.0",
+    "gatsby-plugin-mailchimp": "^5.0.0",
     "gatsby-plugin-manifest": "^2.0.20",
     "gatsby-plugin-offline": "^2.0.24",
     "gatsby-plugin-react-helmet": "^3.0.7",