Fix the feature dtypes

README.md

@@ -47,11 +47,11 @@ Collection of ASCII art from various sources:
 
 ```python
 datasets.Features({
-    'caption': datasets.features.Value(dtype='uint64'),
-    'content': datasets.features.Value(dtype='uint64'),
-    'labels': datasets.features.Value(dtype='large_binary'),
-    'charsets': datasets.features.Value(dtype='large_binary'),
-    'chartypes': datasets.features.Value(dtype='large_binary'),})
+    'caption': datasets.features.Value(dtype='string'),
+    'content': datasets.features.Value(dtype='string'),
+    'labels': datasets.features.Value(dtype='string'),
+    'charsets': datasets.features.Value(dtype='string'),
+    'chartypes': datasets.features.Value(dtype='string'),})
 ```
 
 [github-scrapscii]: https://github.com/apehex/scrapscii/