New Gatsby plugin for Decap is now available
The deprecated gatsby-plugin-netlify-cms that corresponds to the old Netlify CMS package is now deprecated and replaced by gatsby-plugin-decap-cms.
To migrate you Gatsby site from Netlify CMS 2 to Decap CMS 3:
- uninstall gatsby-plugin-netlify-cms and netlify-cms-app
 - install gatsby-plugin-netlify-cms and decap-cms-app
 - replace the import 
import CMS from "netlify-cms-app"withimport CMS from "decap-cms-app" - in gatsby config replace 
resolve: "gatsby-plugin-netlify-cms"withresolve: "gatsby-plugin-decap-cms" 
An example of a migration can be found in this PR on the Decap-Gatsby starter template.