Replace YAML keys from int to str

Replace YAML metadata integer keys with strings, as the Hub does not support integers.
See: https://github.com/huggingface/datasets/issues/5275

README.md

@@ -9,7 +9,6 @@ license:
 - cc0-1.0
 multilinguality:
 - monolingual
-pretty_name: Jigsaw Unintended Bias in Toxicity Classification
 size_categories:
 - 1M<n<10M
 source_datasets:
@@ -18,6 +17,7 @@ task_categories:
 - text-classification
 task_ids:
 - text-scoring
+pretty_name: Jigsaw Unintended Bias in Toxicity Classification
 tags:
 - toxicity-prediction
 dataset_info:
@@ -96,8 +96,8 @@ dataset_info:
     dtype:
       class_label:
         names:
-          0: rejected
-          1: approved
+          '0': rejected
+          '1': approved
   - name: funny
     dtype: int32
   - name: wow