Add metro-core to the package.jsons that use it

Reviewed By: rafeca

Differential Revision: D6578053

fbshipit-source-id: b9d4e2e5820854ffe0e9cb54a78436d0ef2917ce

Author: Peter van der Zee

package.json

@@ -171,6 +171,7 @@
     "inquirer": "^3.0.6",
     "lodash": "^4.16.6",
     "metro": "^0.23.0",
+    "metro-core": "^0.23.0",
     "mime": "^1.3.4",
     "minimist": "^1.2.0",
     "mkdirp": "^0.5.1",