Reverted back devDependency.

Author: Martynas Žilinskas

packages/simplr-forms-core/package.json

@@ -19,6 +19,7 @@
     "enzyme": "^2.8.0",
     "jest": "^19.0.2",
     "jest-enzyme": "^3.0.0",
+    "react-addons-test-utils": "^15.5.1",
     "sinon": "^2.1.0",
     "ts-jest": "^19.0.8",
     "tslint": "^5.0.0",
@@ -51,4 +52,4 @@
       "js"
     ]
   }
-}
+}