[Security] Bump superagent from 1.8.5 to 5.1.0
[Security] Bump superagent from 1.8.5 to 5.1.0

Bumps [superagent](https://github.com/visionmedia/superagent) from 1.8.5 to 5.1.0. **This update includes security fixes.**
- [Release notes](https://github.com/visionmedia/superagent/releases)
- [Changelog](https://github.com/visionmedia/superagent/blob/master/HISTORY.md)
- [Commits](https://github.com/visionmedia/superagent/commits/v5.1.0)

Signed-off-by: dependabot-preview[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
andela-ekupara/DcManFrontEnd,andela-ekupara/DcManFrontEnd