unCLIP scheduler do not use note (huggingface#3417)

Author: williamberman

src/diffusers/schedulers/scheduling_unclip.py

@@ -75,6 +75,9 @@ def alpha_bar(time_step):
 
 class UnCLIPScheduler(SchedulerMixin, ConfigMixin):
     """
+    NOTE: do not use this scheduler. The DDPM scheduler has been updated to support the changes made here. This
+    scheduler will be removed and replaced with DDPM.
+
     This is a modified DDPM Scheduler specifically for the karlo unCLIP model.
 
     This scheduler has some minor variations in how it calculates the learned range variance and dynamically