Convert dataset sizes from base 2 to base 10 in the dataset card

Convert dataset sizes from base 2 (MiB) to base 10 (MB) in the dataset card, as it is the case in the dataset viewer.
See: https://github.com/huggingface/datasets/issues/5708

README.md

@@ -85,9 +85,9 @@ dataset_info:
 - **Leaderboard:** [Gigaword leaderboard](https://paperswithcode.com/sota/text-summarization-on-gigaword)
 - **Paper:** [A Neural Attention Model for Abstractive Sentence Summarization](https://arxiv.org/abs/1509.00685)
 - **Point of Contact:** [Alexander Rush](mailto:arush@cornell.edu)
-- **Size of downloaded dataset files:** 551.61 MB
-- **Size of the generated dataset:** 918.35 MB
-- **Total amount of disk used:** 1469.96 MB
+- **Size of downloaded dataset files:** 578.41 MB
+- **Size of the generated dataset:** 962.96 MB
+- **Total amount of disk used:** 1.54 GB
 
 ### Dataset Summary