Bump pyopenssl in /hooks/python/flask-github-webhooks

Bumps [pyopenssl](https://github.com/pyca/pyopenssl) from 16.2.0 to 17.5.0.
- [Release notes](https://github.com/pyca/pyopenssl/releases)
- [Changelog](https://github.com/pyca/pyopenssl/blob/main/CHANGELOG.rst)
- [Commits](pyca/pyopenssl@16.2.0...17.5.0)

---
updated-dependencies:
- dependency-name: pyopenssl
  dependency-type: direct:production
...

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

Author: dependabot[bot]

hooks/python/flask-github-webhooks/requirements.txt

@@ -1,4 +1,4 @@
 Flask
 ipaddress
 requests
-pyOpenSSL==16.2.0
+pyOpenSSL==17.5.0