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

@@ -1,8 +1,27 @@
 ---
 language:
 - en
-paperswithcode_id: null
 pretty_name: YelpPolarity
+dataset_info:
+  features:
+  - name: text
+    dtype: string
+  - name: label
+    dtype:
+      class_label:
+        names:
+          '0': '1'
+          '1': '2'
+  config_name: plain_text
+  splits:
+  - name: train
+    num_bytes: 413558837
+    num_examples: 560000
+  - name: test
+    num_bytes: 27962097
+    num_examples: 38000
+  download_size: 166373201
+  dataset_size: 441520934
 train-eval-index:
 - config: plain_text
   task: text-classification
@@ -44,26 +63,6 @@ train-eval-index:
     name: Recall weighted
     args:
       average: weighted
-dataset_info:
-  features:
-  - name: text
-    dtype: string
-  - name: label
-    dtype:
-      class_label:
-        names:
-          0: '1'
-          1: '2'
-  config_name: plain_text
-  splits:
-  - name: train
-    num_bytes: 413558837
-    num_examples: 560000
-  - name: test
-    num_bytes: 27962097
-    num_examples: 38000
-  download_size: 166373201
-  dataset_size: 441520934
 ---
 
 # Dataset Card for "yelp_polarity"