Bump mypy to 1.0 (#9684)

stubs/paramiko/paramiko/util.pyi

@@ -42,5 +42,5 @@ def clamp_value(minimum: int, val: int, maximum: int) -> int: ...
 # This function attempts to convert objects to bytes,
 # *but* just returns the object unchanged if that was unsuccessful!
 def asbytes(s: object) -> object: ...
-def b(s: str | bytes, encoding: str = "utf-8") -> bytes: ...
-def u(s: str | bytes, encoding: str = "utf-8") -> str: ...
+def b(s: str | bytes, encoding: str = "utf8") -> bytes: ...
+def u(s: str | bytes, encoding: str = "utf8") -> str: ...