Remove deprecated tasks

This dataset uses `tasks`, which are deprecated and will raise an error after the next major release of `datasets`. See: https://github.com/huggingface/datasets/pull/6999

dblp-discovery-dataset.py

@@ -20,7 +20,6 @@ import os
 from typing import Any, Dict, Generator, List, Optional, Tuple, Union
 
 import datasets
-from datasets.tasks import TextClassification
 from lxml import etree
 
 logger = datasets.logging.get_logger(__name__)