update deps

package.json

     "eslint-config-xo-react": "0.13.x",
     "eslint-plugin-react": "7.x.x",
     "detox": "5.x.x",
-    "jest": "20.x.x",
+    "jest": "21.x.x",
     "mocha": "3.x.x",
     "react": "16.0.0-alpha.6",
     "react-native": "0.44.0",
     "react-test-renderer": "16.0.0-alpha.6",
-    "remx": "1.x.x",
+    "remx": "2.x.x",
     "semver": "5.x.x",
     "shell-utils": "1.x.x"
   },