Update example HTTP driver version

Author: lmatteis

example/package.json

@@ -12,7 +12,7 @@
   "author": "Luca Matteis",
   "license": "MIT",
   "dependencies": {
-    "@cycle/http": "^11.2.0",
+    "@cycle/http": "^12.0.0",
     "@cycle/run": "^1.0.0",
     "history": "^2.1.2",
     "react": "^15.3.0",