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

@@ -17,8 +17,29 @@ task_categories:
 - text-classification
 task_ids:
 - sentiment-classification
-paperswithcode_id: null
 pretty_name: Amazon Review Polarity
+dataset_info:
+  features:
+  - name: label
+    dtype:
+      class_label:
+        names:
+          '0': negative
+          '1': positive
+  - name: title
+    dtype: string
+  - name: content
+    dtype: string
+  config_name: amazon_polarity
+  splits:
+  - name: train
+    num_bytes: 1604364432
+    num_examples: 3600000
+  - name: test
+    num_bytes: 178176193
+    num_examples: 400000
+  download_size: 688339454
+  dataset_size: 1782540625
 train-eval-index:
 - config: amazon_polarity
   task: text-classification
@@ -68,28 +89,6 @@ train-eval-index:
     name: Recall weighted
     args:
       average: weighted
-dataset_info:
-  features:
-  - name: label
-    dtype:
-      class_label:
-        names:
-          0: negative
-          1: positive
-  - name: title
-    dtype: string
-  - name: content
-    dtype: string
-  config_name: amazon_polarity
-  splits:
-  - name: train
-    num_bytes: 1604364432
-    num_examples: 3600000
-  - name: test
-    num_bytes: 178176193
-    num_examples: 400000
-  download_size: 688339454
-  dataset_size: 1782540625
 ---
 
 # Dataset Card for Amazon Review Polarity