Add Greenkeeper badge 🌴 (#615)

* chore: add Greenkeeper config file

* move greenkeeper config into package.json

package.json

@@ -72,15 +72,25 @@
     ]
   },
   "greenkeeper": {
+    "groups": {
+      "app": {
+        "packages": [
+          "package.json"
+        ],
         "ignore": [
           "graphql",
-      "react",
-      "react-dnd",
           "react-dnd-html5-backend",
           "react-dom",
           "webpack"
         ]
       },
+      "integrations": {
+        "packages": [
+          "packages/gatsby-remark-embed-carbon/package.json"
+        ]
+      }
+    }
+  },
   "description": "Create and share beautiful images of your source code",
   "repository": {
     "type": "git",