Add is_secure_transport function signature

Author: mrhx01

stubs/Authlib/authlib/common/security.pyi

@@ -3,4 +3,5 @@ from typing import Final
 UNICODE_ASCII_CHARACTER_SET: Final[str]
 
 def generate_token(length: int = 30, chars: str = UNICODE_ASCII_CHARACTER_SET) -> str: ...
+
 def is_secure_transport(uri: str) -> bool: ...