build(deps-dev): Bump @types/serve-index from 1.9.3 to 1.9.4 (#1467)

Bumps [@types/serve-index](https://github.com/DefinitelyTyped/DefinitelyTyped/tree/HEAD/types/serve-index) from 1.9.3 to 1.9.4.
- [Release notes](https://github.com/DefinitelyTyped/DefinitelyTyped/releases)
- [Commits](https://github.com/DefinitelyTyped/DefinitelyTyped/commits/HEAD/types/serve-index)

---
updated-dependencies:
- dependency-name: "@types/serve-index"
  dependency-type: indirect
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>