update doc

Author: blink1073

requirements/ocsp.txt

@@ -4,6 +4,7 @@
 # service_identity 18.1.0 introduced support for IP addr matching.
 # Fallback to certifi on Windows if we can't load CA certs from the system
 # store and just use certifi on macOS.
+# pyopenssl, cryptography, and service_identity must be set in tandem.
 # https://www.pyopenssl.org/en/stable/api/ssl.html#OpenSSL.SSL.Context.set_default_verify_paths
 certifi>=2023.7.22;os.name=='nt' or sys_platform=='darwin'
 pyopenssl>=23.2.0