fix(package): update deepmerge to version 2.0.0

Author: greenkeeper[bot]

package.json

@@ -36,7 +36,7 @@
         "node": ">= 4.3 < 5.0.0 || >= 5.10"
     },
     "dependencies": {
-        "deepmerge": "^1.3.2"
+        "deepmerge": "^2.0.0"
     },
     "devDependencies": {
         "browser-sync": "^2.18.8",