add dataclass decorator to DependencyParsingOutput

src/adapters/heads/dependency_parsing.py

@@ -2,6 +2,7 @@
 Code taken and modified from: https://github.com/Adapter-Hub/hgiyt. Credits: "How Good is Your Tokenizer? On the
 Monolingual Performance of Multilingual Language Models" (Rust et al., 2021) https://arxiv.org/abs/2012.15613
 """
+from dataclasses import dataclass
 from typing import Optional, Tuple
 
 import torch
@@ -13,6 +14,7 @@
 from .base import PredictionHead
 
 
+@dataclass
 class DependencyParsingOutput(ModelOutput):
     loss: Optional[torch.FloatTensor] = None
     rel_preds: torch.FloatTensor = None