Bump pyopenssl from 18.0.0 to 21.0.0

Bumps [pyopenssl](https://github.com/pyca/pyopenssl) from 18.0.0 to 21.0.0.
- [Release notes](https://github.com/pyca/pyopenssl/releases)
- [Changelog](https://github.com/pyca/pyopenssl/blob/main/CHANGELOG.rst)
- [Commits](https://github.com/pyca/pyopenssl/compare/18.0.0...21.0.0)

---
updated-dependencies:
- dependency-name: pyopenssl
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

requirements.txt

@@ -24,7 +24,7 @@ protobuf==3.19.1
 pyasn1==0.4.8
 pyasn1-modules==0.2.8
 pycparser==2.21
-pyOpenSSL==20.0.1
+pyOpenSSL==21.0.0
 pytz==2021.3
 PyYAML==5.4.1
 redis==3.5.3