Merge pull request #36 from szhechev/float64_error_fix

Fixed a problem with a numpy 1.18 deprecation

Author: Nathaniel Saul

persim/images.py

@@ -91,7 +91,7 @@ def transform(self, diagrams):
         if singular:
             diagrams = [diagrams]
 
-        dgs = [np.copy(diagram, np.float64) for diagram in diagrams]
+        dgs = [np.copy(diagram) for diagram in diagrams]
         landscapes = [PersImage.to_landscape(dg) for dg in dgs]
 
         if not self.specs: