GH-467: fix ArtifactoryPath.__reduce__ for python 3.9 and below

artifactory.py

@@ -1569,7 +1569,13 @@ def __reduce__(self):
         # pathlib.PurePath.__reduce__ doesn't include instance state, but we
         # have state that needs to be included when pickling
         pathlib_reduce = super().__reduce__()
-        return pathlib_reduce[0], pathlib_reduce[1], self.__dict__
+        # pathlib.Path in 3.10+ does not have __slots__, so self.__dict__ is available;
+        # in 3.9 and earlier there is no self.__dict__. return slots instead
+        if sys.version_info.major == 3 and sys.version_info.minor >= 10:
+            attributes = self.__dict__
+        else:
+            attributes = {x: getattr(self, x) for x in self.__slots__}
+        return pathlib_reduce[0], pathlib_reduce[1], attributes
 
     @property
     def top(self):