Indicating immutable 4 support in package.json

Author: D1plo1d

package.json

@@ -72,7 +72,7 @@
     "eslint-plugin-import": "^2.7.0",
     "eslint-plugin-jsx-a11y": "^5.1.1",
     "eslint-plugin-react": "^7.4.0",
-    "immutable": "^3.7.6",
+    "immutable": "^3.7.6 || ^4.0.0-rc.1",
     "jest": "^22.4.3",
     "redux-loop": "^4.0.0",
     "rimraf": "^2.6.2",