add TimeAsFeature to transform registry (#2439)

Summary:

see title

Reviewed By: bernardbeckerman

Differential Revision: D57119551

ax/storage/transform_registry.py

@@ -40,6 +40,7 @@
 from ax.modelbridge.transforms.standardize_y import StandardizeY
 from ax.modelbridge.transforms.stratified_standardize_y import StratifiedStandardizeY
 from ax.modelbridge.transforms.task_encode import TaskEncode
+from ax.modelbridge.transforms.time_as_feature import TimeAsFeature
 from ax.modelbridge.transforms.trial_as_task import TrialAsTask
 from ax.modelbridge.transforms.unit_x import UnitX
 from ax.modelbridge.transforms.winsorize import Winsorize
@@ -90,6 +91,7 @@
     Relativize: 24,
     RelativizeWithConstantControl: 25,
     MergeRepeatedMeasurements: 26,
+    TimeAsFeature: 27,
 }
 
 """