Update bibtex to ACL version

README.md

@@ -68,11 +68,16 @@ semantic_sim = 1 - cosine(embeddings[0], embeddings[1])
 ### BibTeX entry and citation info
 
 ```bibtex
-@article{Giorgi2020DeCLUTRDC,
-  title={DeCLUTR: Deep Contrastive Learning for Unsupervised Textual Representations},
-  author={John M Giorgi and Osvald Nitski and Gary D. Bader and Bo Wang},
-  journal={ArXiv},
-  year={2020},
-  volume={abs/2006.03659}
+@inproceedings{giorgi-etal-2021-declutr,
+    title        = {{D}e{CLUTR}: Deep Contrastive Learning for Unsupervised Textual Representations},
+    author       = {Giorgi, John  and Nitski, Osvald  and Wang, Bo  and Bader, Gary},
+    year         = 2021,
+    month        = aug,
+    booktitle    = {Proceedings of the 59th Annual Meeting of the Association for Computational Linguistics and the 11th International Joint Conference on Natural Language Processing (Volume 1: Long Papers)},
+    publisher    = {Association for Computational Linguistics},
+    address      = {Online},
+    pages        = {879--895},
+    doi          = {10.18653/v1/2021.acl-long.72},
+    url          = {https://aclanthology.org/2021.acl-long.72}
 }
 ```