Bump browser-pack-flat from 3.4.2 to 3.5.0

Bumps [browser-pack-flat](https://github.com/goto-bus-stop/browser-pack-flat) from 3.4.2 to 3.5.0.
- [Release notes](https://github.com/goto-bus-stop/browser-pack-flat/releases)
- [Changelog](https://github.com/goto-bus-stop/browser-pack-flat/blob/default/CHANGELOG.md)
- [Commits](goto-bus-stop/browser-pack-flat@v3.4.2...v3.5.0)

---
updated-dependencies:
- dependency-name: browser-pack-flat
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

package-lock.json

@@ -18,7 +18,7 @@
     "@fontsource/open-sans": "^5.0.3",
     "@fontsource/roboto-mono": "~5.0",
     "autoprefixer": "~9.7",
-    "browser-pack-flat": "~3.4",
+    "browser-pack-flat": "~3.5",
     "browserify": "~17.0",
     "cssnano": "~4.1",
     "eslint": "~6.8",