Bump axios from 0.21.4 to 0.28.0 in /backend

Bumps [axios](https://github.com/axios/axios) from 0.21.4 to 0.28.0.
- [Release notes](https://github.com/axios/axios/releases)
- [Changelog](https://github.com/axios/axios/blob/v0.28.0/CHANGELOG.md)
- [Commits](axios/axios@v0.21.4...v0.28.0)

---
updated-dependencies:
- dependency-name: axios
  dependency-type: direct:production
...

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Author: dependabot[bot]