chore(deps): bump serde_ipld_dagjson from 0.2.0 to 0.2.1 in /rust (#170)

Bumps [serde_ipld_dagjson](https://github.com/ipld/serde_ipld_dagjson) from 0.2.0 to 0.2.1.
- [Commits](ipld/serde_ipld_dagjson@v0.2.0...v0.2.1)

---
updated-dependencies:
- dependency-name: serde_ipld_dagjson
  dependency-version: 0.2.1
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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Author: dependabot[bot]