Bump tokio-test from 0.4.2 to 0.4.3 in /cmd/pinniped-proxy

Bumps [tokio-test](https://github.com/tokio-rs/tokio) from 0.4.2 to 0.4.3.
- [Release notes](https://github.com/tokio-rs/tokio/releases)
- [Commits](tokio-rs/tokio@tokio-test-0.4.2...tokio-test-0.4.3)

---
updated-dependencies:
- dependency-name: tokio-test
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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