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

@@ -16,7 +16,6 @@ license:
 - cc0-1.0
 multilinguality:
 - multilingual
-pretty_name: BnL Historical Newspapers
 size_categories:
 - 100K<n<1M
 source_datasets:
@@ -27,6 +26,7 @@ task_categories:
 task_ids:
 - language-modeling
 - masked-language-modeling
+pretty_name: BnL Historical Newspapers
 dataset_info:
   features:
   - name: id
@@ -51,24 +51,24 @@ dataset_info:
     dtype:
       class_label:
         names:
-          0: ADVERTISEMENT_SECTION
-          1: BIBLIOGRAPHY
-          2: CHAPTER
-          3: INDEX
-          4: CONTRIBUTION
-          5: TABLE_OF_CONTENTS
-          6: WEATHER
-          7: SHIPPING
-          8: SECTION
-          9: ARTICLE
-          10: TITLE_SECTION
-          11: DEATH_NOTICE
-          12: SUPPLEMENT
-          13: TABLE
-          14: ADVERTISEMENT
-          15: CHART_DIAGRAM
-          16: ILLUSTRATION
-          17: ISSUE
+          '0': ADVERTISEMENT_SECTION
+          '1': BIBLIOGRAPHY
+          '2': CHAPTER
+          '3': INDEX
+          '4': CONTRIBUTION
+          '5': TABLE_OF_CONTENTS
+          '6': WEATHER
+          '7': SHIPPING
+          '8': SECTION
+          '9': ARTICLE
+          '10': TITLE_SECTION
+          '11': DEATH_NOTICE
+          '12': SUPPLEMENT
+          '13': TABLE
+          '14': ADVERTISEMENT
+          '15': CHART_DIAGRAM
+          '16': ILLUSTRATION
+          '17': ISSUE
   - name: extent
     dtype: int32
   config_name: processed