Issue #19921: When Path.mkdir() is called with parents=True, any missing parent is created with the default permissions, ignoring the mode argument (mimicking the POSIX "mkdir -p" command).

Patch by Serhiy.
diff --git a/Lib/pathlib.py b/Lib/pathlib.py
index 9b4fde1..18facd9 100644
--- a/Lib/pathlib.py
+++ b/Lib/pathlib.py
@@ -1101,7 +1101,7 @@
             except OSError as e:
                 if e.errno != ENOENT:
                     raise
-                self.parent.mkdir(mode, True)
+                self.parent.mkdir(parents=True)
                 self._accessor.mkdir(self, mode)
 
     def chmod(self, mode):