prop-types moved from dependencies to devDependencies

Author: pmajkutewicz

package.json

@@ -52,6 +52,7 @@
     "eslint-plugin-lean-imports": "^0.3.3",
     "eslint-plugin-react": "^4.2.3",
     "leaflet": "^1.0.0",
+    "prop-types": "^15.5.10",
     "react": "^15.4.1",
     "react-addons-test-utils": "^0.14.7",
     "react-dom": "^15.4.1",
@@ -69,7 +70,6 @@
     "lodash.min": "^4.0.0",
     "lodash.pluck": "^3.1.2",
     "lodash.reduce": "^4.3.0",
-    "prop-types": "^15.5.10",
     "simpleheat": "^0.4.0"
   }
 }