Upgrade rsocket packages (#779)

Summary:
Pull Request resolved: https://github.com/facebook/flipper/pull/779

Close https://github.com/facebook/flipper/pull/773
Close https://github.com/facebook/flipper/pull/774

Reviewed By: nikoant

Differential Revision: D19771979

fbshipit-source-id: c56b655a3cfb428d60f221a653b2d689d2a71fb0

package.json

@@ -180,8 +180,8 @@
     "redux": "^4.0.0",
     "redux-persist": "^6.0.0",
     "remote-redux-devtools": "^0.5.16",
-    "rsocket-core": "^0.0.18",
-    "rsocket-tcp-server": "^0.0.18",
+    "rsocket-core": "^0.0.19",
+    "rsocket-tcp-server": "^0.0.19",
     "socket.io": "^2.0.4",
     "string-natural-compare": "^3.0.0",
     "tmp": "0.0.33",