Use torch.det to calculate volumes

`torch.cross` without `dim` is deprecated.

Author: tsihyoung

chgnet/model/model.py

@@ -807,7 +807,7 @@ def from_graphs(
             else:
                 strain = None
                 lattice = graph.lattice
-            volumes.append(torch.dot(lattice[0], torch.cross(lattice[1], lattice[2])))
+            volumes.append(torch.det(lattice))
             strains.append(strain)
 
             # Bonds