Bump cryptography in /sample-apps/starlette-postgres-uvicorn

Bumps [cryptography](https://github.com/pyca/cryptography) from 44.0.0 to 50.0.0.
- [Changelog](https://github.com/pyca/cryptography/blob/main/CHANGELOG.rst)
- [Commits](pyca/cryptography@44.0.0...50.0.0)

---
updated-dependencies:
- dependency-name: cryptography
  dependency-version: 50.0.0
  dependency-type: direct:production
...

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Author: dependabot[bot]