Bump lodash from 4.17.20 to 4.17.21 in /app/server

Bumps [lodash](https://github.com/lodash/lodash) from 4.17.20 to 4.17.21.
- [Release notes](https://github.com/lodash/lodash/releases)
- [Commits](https://github.com/lodash/lodash/compare/4.17.20...4.17.21

)

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