Fix task_categories

The list of available tasks is here: https://github.com/huggingface/hub-docs/blob/main/js/src/lib/interfaces/Types.ts#L85

README.md

@@ -13,13 +13,13 @@ size_categories:
 - unknown
 source_datasets:
 - original
-task_categories:
-- structure-prediction
-- code-generation
-- conditional-text-generation
+task_categories: []
 task_ids: []
 pretty_name: Lynx
 tags:
+- structure-prediction
+- code-generation
+- conditional-text-generation
 - word-segmentation
 ---