cargo: bump serde in the cargo-dependencies group

Bumps the cargo-dependencies group with 1 update: [serde](https://github.com/serde-rs/serde).


Updates `serde` from 1.0.215 to 1.0.216
- [Release notes](https://github.com/serde-rs/serde/releases)
- [Commits](serde-rs/serde@v1.0.215...v1.0.216)

---
updated-dependencies:
- dependency-name: serde
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: cargo-dependencies
...

Signed-off-by: dependabot[bot] <[email protected]>