fix type

Author: denini08

tests/test_trustme.py

@@ -284,7 +284,7 @@ def test_ca_from_pem(tmp_path: Path) -> None:
     assert ca1.private_key_pem.bytes() == ca2.private_key_pem.bytes()
 
 
-def safe_close(sock: Optional[socket.socket]) -> None:
+def safe_close(sock: Optional[Union[socket.socket, SslSocket]]) -> None:
     if sock is None:
         return
     try: