Bump @rails/webpacker from 5.2.1 to 5.4.0 (#9640)

Bumps [@rails/webpacker](https://github.com/rails/webpacker) from 5.2.1 to 5.4.0.
- [Release notes](https://github.com/rails/webpacker/releases)
- [Changelog](https://github.com/rails/webpacker/blob/master/CHANGELOG.md)
- [Commits](rails/webpacker@v5.2.1...v5.4.0)

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package.json

@@ -19,7 +19,7 @@
   },
   "dependencies": {
     "@babel/preset-react": "^7.13.13",
-    "@rails/webpacker": "5.2.1",
+    "@rails/webpacker": "5.4.0",
     "babel-plugin-transform-react-remove-prop-types": "^0.4.24",
     "blob.js": "^1.0.1",
     "blueimp-file-upload": "blueimp/jQuery-File-Upload#^10.31.0",