Update dependency deepmerge to v4.3.1

Author: renovate[bot]

package.json

@@ -3,7 +3,7 @@
 
         "@symfony/webpack-encore": "4.0.0",
         "core-js": "3.25.5",
-        "deepmerge": "4.2.2",
+        "deepmerge": "4.3.1",
         "fibers": "5.0.3",
         "node-sass": "7.0.3",
         "regenerator-runtime": "0.13.9",