Update lion_pytorch.py

This function already does summation in place, and therefore errors out when the inplace parameters is passed into the _add func.

lion/lion_pytorch.py

@@ -78,7 +78,7 @@ def step(self, closure=None):
         # Weight update
         update = exp_avg * beta1 + grad * (1 - beta1)
 
-        p.add_(torch.sign(update), alpha=-group['lr'], inplace=True)
+        p.add_(torch.sign(update), alpha=-group['lr'])
         #This has been made more efficient by using the torch.sign function's inplace mode. 
         #This will prevent the need to create a new tensor for the updated parameter, 
         #which can save a significant amount of time for large models.