Bump copy-webpack-plugin from 13.0.1 to 14.0.0 in /wgpu-testbed-webapp (#363)

Bumps [copy-webpack-plugin](https://github.com/webpack/copy-webpack-plugin) from 13.0.1 to 14.0.0.
- [Release notes](https://github.com/webpack/copy-webpack-plugin/releases)
- [Changelog](https://github.com/webpack/copy-webpack-plugin/blob/main/CHANGELOG.md)
- [Commits](webpack/copy-webpack-plugin@v13.0.1...v14.0.0)

---
updated-dependencies:
- dependency-name: copy-webpack-plugin
  dependency-version: 14.0.0
  dependency-type: direct:development
  update-type: version-update:semver-major
...

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Author: dependabot[bot]

wgpu-testbed-webapp/package-lock.json

@@ -9,7 +9,7 @@
   },
   "author": "Hugo Woodiwiss <hj.woodiwiss@gmail.com>",
   "devDependencies": {
-    "copy-webpack-plugin": "^13.0.1",
+    "copy-webpack-plugin": "^14.0.0",
     "prettier": "^3.8.1",
     "webpack": "^5.105.2",
     "webpack-cli": "^6.0.1",