Fixed type hint failure for Python <= 3.8
Python <= 3.8 interprets "list" (lowercase) as a type and throws an error when trying to index into it as a type-hint.  Converted to uppercase "List".
@@ -95,7 +95,7 @@ def _zero_pad(sequence_length: int) -> datasets.Transform:
def _make_adder_config(step_spec: reverb_base.Step, seq_len: int,
- seq_period: int) -> list[sw.Config]:
+ seq_period: int) -> List[sw.Config]:
return structured.create_sequence_config(
step_spec=step_spec,
sequence_length=seq_len,
