Bump mini_racer from 0.3.1 to 0.4.0
Bump mini_racer from 0.3.1 to 0.4.0

Bumps [mini_racer](https://github.com/discourse/mini_racer) from 0.3.1 to 0.4.0.
- [Release notes](https://github.com/discourse/mini_racer/releases)
- [Changelog](https://github.com/rubyjs/mini_racer/blob/master/CHANGELOG)
- [Commits](https://github.com/discourse/mini_racer/compare/v0.3.1...v0.4.0)

Signed-off-by: dependabot-preview[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
mitre-cyber-academy/ctf-scoreboard,mitre-cyber-academy/ctf-scoreboard,mitre-cyber-academy/ctf-scoreboard,mitre-cyber-academy/ctf-scoreboard