chore: remove deep-assign (#5079)

Author: zkwolf

package.json

@@ -136,7 +136,6 @@
     "css-loader": "^5.0.0",
     "css-minimizer-webpack-plugin": "^3.0.0",
     "date-fns": "^2.24.0",
-    "deep-assign": "^3.0.0",
     "diacritics": "^1.3.0",
     "docsearch.js": "^2.6.3",
     "enquire-js": "^0.2.1",