Revert "fix: /Users/runner/work/chgnet/chgnet/chgnet/model/dynamics.p…

…y:297: DeprecationWarning: Use FrechetCellFilter for better convergence w.r.t. cell variables."

This reverts commit b60f5e4.

chgnet/model/dynamics.py

@@ -11,7 +11,6 @@
 import numpy as np
 from ase import Atoms, units
 from ase.calculators.calculator import Calculator, all_changes, all_properties
-from ase.filters import FrechetCellFilter
 from ase.md.npt import NPT
 from ase.md.nptberendsen import Inhomogeneous_NPTBerendsen, NPTBerendsen, NVTBerendsen
 from ase.md.velocitydistribution import MaxwellBoltzmannDistribution, Stationary
@@ -295,7 +294,7 @@ def relax(
                 cry_obs = CrystalFeasObserver(atoms)
 
             if relax_cell:
-                atoms = FrechetCellFilter(atoms)
+                atoms = ase_filter(atoms)
             optimizer: Optimizer = self.optimizer_class(atoms, **kwargs)
             optimizer.attach(obs, interval=loginterval)