chore(package): update gulp-merge-json to version 2.1.1

Closes #70

Author: greenkeeper[bot]

package.json

@@ -42,7 +42,7 @@
     "gulp-if": "^2.0.2",
     "gulp-livereload": "^4.0.0",
     "gulp-load-plugins": "^1.5.0",
-    "gulp-merge-json": "^1.0.0",
+    "gulp-merge-json": "^2.1.1",
     "gulp-plumber": "^1.1.0",
     "gulp-rename": "^1.2.2",
     "gulp-run-sequence": "*",