Bump express from 4.15.3 to 4.18.2 in /frontend

Bumps [express](https://github.com/expressjs/express) from 4.15.3 to 4.18.2. - [Release notes](https://github.com/expressjs/express/releases) - [Changelog](https://github.com/expressjs/express/blob/master/History.md) - [Commits](expressjs/express@4.15.3...4.18.2) --- updated-dependencies: - dependency-name: express dependency-type: indirect ... Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]