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

@@ -2,15 +2,14 @@
 annotations_creators:
 - crowdsourced
 - machine-generated
-language:
-- en
 language_creators:
 - found
+language:
+- en
 license:
 - cc-by-nc-4.0
 multilinguality:
 - monolingual
-pretty_name: Adversarial NLI
 size_categories:
 - 100K<n<1M
 source_datasets:
@@ -22,6 +21,7 @@ task_ids:
 - natural-language-inference
 - multi-input-text-classification
 paperswithcode_id: anli
+pretty_name: Adversarial NLI
 dataset_info:
   features:
   - name: uid
@@ -34,9 +34,9 @@ dataset_info:
     dtype:
       class_label:
         names:
-          0: entailment
-          1: neutral
-          2: contradiction
+          '0': entailment
+          '1': neutral
+          '2': contradiction
   - name: reason
     dtype: string
   config_name: plain_text