pyOpenSSL: Add DTLS_* constants (#11486)

stubs/pyOpenSSL/OpenSSL/SSL.pyi

@@ -24,6 +24,9 @@ TLSv1_2_METHOD: int
 TLS_METHOD: int
 TLS_SERVER_METHOD: int
 TLS_CLIENT_METHOD: int
+DTLS_METHOD: int
+DTLS_SERVER_METHOD: int
+DTLS_CLIENT_METHOD: int
 
 SSL3_VERSION: int
 TLS1_VERSION: int