Bump wasm-bindgen-futures from 0.4.34 to 0.4.42 in /example

Bumps [wasm-bindgen-futures](https://github.com/rustwasm/wasm-bindgen) from 0.4.34 to 0.4.42.
- [Release notes](https://github.com/rustwasm/wasm-bindgen/releases)
- [Changelog](https://github.com/rustwasm/wasm-bindgen/blob/main/CHANGELOG.md)
- [Commits](https://github.com/rustwasm/wasm-bindgen/commits)

---
updated-dependencies:
- dependency-name: wasm-bindgen-futures
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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