chore(deps): bump cryptography in /privateca/snippets

Bumps [cryptography](https://github.com/pyca/cryptography) from 48.0.1 to 50.0.0.
- [Changelog](https://github.com/pyca/cryptography/blob/main/CHANGELOG.rst)
- [Commits](pyca/cryptography@48.0.1...50.0.0)

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

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

privateca/snippets/requirements-test.txt

@@ -1,4 +1,4 @@
 pytest==9.0.3
 google-auth==2.38.0
-cryptography==48.0.1
+cryptography==50.0.0
 backoff==2.2.1