Upgrade black version (#7089)

stdlib/subprocess.pyi

@@ -991,6 +991,7 @@ class Popen(Generic[AnyStr]):
             encoding: str | None = ...,
             errors: str | None = ...,
         ) -> Popen[Any]: ...
+
     def poll(self) -> int | None: ...
     if sys.version_info >= (3, 7):
         def wait(self, timeout: float | None = ...) -> int: ...