Bump serialize-javascript from 6.0.0 to 6.0.2 in /examples/grpc-web

Bumps [serialize-javascript](https://github.com/yahoo/serialize-javascript) from 6.0.0 to 6.0.2.
- [Release notes](https://github.com/yahoo/serialize-javascript/releases)
- [Commits](yahoo/serialize-javascript@v6.0.0...v6.0.2)

---
updated-dependencies:
- dependency-name: serialize-javascript
  dependency-type: indirect
...

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

Author: dependabot[bot]