chore(package): update @types/jsonfile to version 6.0.0

Closes #9

Author: greenkeeper[bot]

package.json

@@ -31,7 +31,7 @@
         "@types/bluebird": "~3.5.24",
         "@types/commander": "~2.12.2",
         "@types/inquirer": "~0.0.43",
-        "@types/jsonfile": "~4.0.1",
+        "@types/jsonfile": "~6.0.0",
         "@types/node": "^10.12.2",
         "@types/webpack-merge": "~4.1.3",
         "np": "~3.0.4",