fix(deps): update dependency deepmerge to v4

Author: renovate-bot

packages/multisite/package.json

@@ -19,7 +19,7 @@
   ],
   "dependencies": {
     "cookie": "^0.3.1",
-    "deepmerge": "2.2.1",
+    "deepmerge": "4.2.2",
     "js-cookie": "^2.2.0"
   },
   "devDependencies": {