Bug: M4 outsample_window may be set improperly

[AdamAbate-6]

See https://github.com/thuml/Time-Series-Library/blob/main/data_provider/data_loader.py#L362

The min value possible for cut_point is 1. This can cause a negative star to the indexing range on line 363. Lines 362 and 363 should read more like this:

outsample_window = sampled_timeseries[
                           max(1, cut_point - self.label_len):min(len(sampled_timeseries), cut_point + self.pred_len)]

in order to avoid the bottom end of the indexing range being negative.