chore(package): update is-plain-obj to version 2.0.0

Author: greenkeeper[bot]

package.json

@@ -48,7 +48,7 @@
 		"eslint": "~4.19.0",
 		"eslint-plugin-wordpress": "git://github.com/WordPress-Coding-Standards/eslint-plugin-wordpress.git#552af1454d175e15f6d25aadc2ccde30a1922d4f",
 		"husky": "~1.3.0",
-		"is-plain-obj": "~1.1.0",
+		"is-plain-obj": "~2.0.0",
 		"jest": "~22.4.2",
 		"npmpub": "~4.1.0"
 	},