Bump the cargo-dependencies group with 2 updates

Bumps the cargo-dependencies group with 2 updates: [paho-mqtt](https://github.com/eclipse/paho.mqtt.rust) and [serde](https://github.com/serde-rs/serde).


Updates `paho-mqtt` from 0.12.4 to 0.12.5
- [Release notes](https://github.com/eclipse/paho.mqtt.rust/releases)
- [Changelog](https://github.com/eclipse/paho.mqtt.rust/blob/master/CHANGELOG.md)
- [Commits](eclipse/paho.mqtt.rust@v0.12.4...v0.12.5)

Updates `serde` from 1.0.202 to 1.0.203
- [Release notes](https://github.com/serde-rs/serde/releases)
- [Commits](serde-rs/serde@v1.0.202...v1.0.203)

---
updated-dependencies:
- dependency-name: paho-mqtt
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: cargo-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]>