build(deps): bump js-sys from 0.3.39 to 0.3.42

Bumps [js-sys](https://github.com/rustwasm/wasm-bindgen) from 0.3.39 to 0.3.42.
- [Release notes](https://github.com/rustwasm/wasm-bindgen/releases)
- [Changelog](https://github.com/rustwasm/wasm-bindgen/blob/master/CHANGELOG.md)
- [Commits](https://github.com/rustwasm/wasm-bindgen/commits)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

dependabot-preview committed Jul 16, 2020

909b4f5