[Security] Bump chartkick from 3.0.2 to 3.2.0
[Security] Bump chartkick from 3.0.2 to 3.2.0

Bumps [chartkick](https://github.com/ankane/chartkick) from 3.0.2 to 3.2.0. **This update includes security fixes.**
- [Release notes](https://github.com/ankane/chartkick/releases)
- [Changelog](https://github.com/ankane/chartkick/blob/master/CHANGELOG.md)
- [Commits](https://github.com/ankane/chartkick/compare/v3.0.2...v3.2.0)
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