Bump serde_with from 3.20.0 to 3.21.0

Bumps [serde_with](https://github.com/jonasbb/serde_with) from 3.20.0 to 3.21.0.
- [Release notes](https://github.com/jonasbb/serde_with/releases)
- [Commits](jonasbb/serde_with@v3.20.0...v3.21.0)

---
updated-dependencies:
- dependency-name: serde_with
  dependency-version: 3.21.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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Author: dependabot[bot]