Bump http-proxy in /examples/canvas_webgl_minimal/www

Bumps [http-proxy](https://github.com/http-party/node-http-proxy) from 1.18.0 to 1.18.1.
- [Release notes](https://github.com/http-party/node-http-proxy/releases)
- [Changelog](https://github.com/http-party/node-http-proxy/blob/master/CHANGELOG.md)
- [Commits](http-party/node-http-proxy@1.18.0...1.18.1)

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