Bump cryptography from 41.0.3 to 41.0.6

Bumps [cryptography](https://github.com/pyca/cryptography) from 41.0.3 to 41.0.6.
- [Changelog](https://github.com/pyca/cryptography/blob/main/CHANGELOG.rst)
- [Commits](pyca/cryptography@41.0.3...41.0.6)

---
updated-dependencies:
- dependency-name: cryptography
  dependency-type: direct:development
...

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

requirements_dev.txt

@@ -6,7 +6,7 @@ flake8==3.4.1
 tox==2.9.1
 coverage==5.5
 Sphinx==3.2.1
-cryptography==41.0.3
+cryptography==41.0.6
 PyYAML==5.4.1
 pytest==3.2.3
 pytest-runner==6.0.0