docs: Update update guide

Author: szuperaz

docusaurus/angular_versioned_docs/version-5/basics/upgrade-v4.mdx

@@ -13,3 +13,12 @@ Angular versions 12-14 are no longer supported. You can use the [Angular update
 
 - Event handlers with `Function` type are changed to `() => void`
 - Event handlers with `any` return types are changed to `void` return type
+
+## Other changes
+
+### Unused packages
+
+The `ngx-popperjs` package has been deprecated, so you can remove the related packages from your `package.json` file:
+
+- `@popperjs/core`
+- `ngx-popperjs`