Update to CFF format. (#696)

Summary:
CITATION.cff file needs to be in a special CFF format, not BibTeX.
Otherwise Github can't use it and complains "Your CITATION.cff file cannot be parsed. Make sure the formatting is correct."
Correct CFF will be converted to BibTex by Github (see https://github.blog/2021-08-19-enhanced-support-citations-github/)

If a separate BibTex file is desired, previous CITATION.cff can be renamed to just CITATION.

Pull Request resolved: #696

Reviewed By: xuzhao9

Differential Revision: D33640556

Pulled By: orionr

fbshipit-source-id: ac8d98e27a222843c7574fca63e758d8b9a650dc

Author: kit1980

CITATION.cff

@@ -1,9 +1,28 @@
-@misc{TorchBench2020,
-    title={TorchBench: A collection of open source benchmarks for PyTorch performance and usability evaluation},
-    author={Will Constable, Xu Zhao, Victor Bittorf, Eric Christoffersen, Taylor Robie, Eric Han, Peng Wu, Nick Korovaiko, Jason Ansel, Orion Reblitz-Richardson, and Soumith Chintala},
-    year={2020},
-    publisher={GitHub},
-    journal={GitHub repository},
-    howpublished={\url{https://github.com/pytorch/benchmark}},
-    primaryClass={cs.PF}
-}
+cff-version: 1.2.0
+title: "TorchBench: A collection of open source benchmarks for PyTorch performance and usability evaluation"
+authors:
+- family-names: Constable
+  given-names: Will
+- family-names: Zhao
+  given-names: Xu
+- family-names: Bittorf
+  given-names: Victor
+- family-names: Christoffersen
+  given-names: Eric
+- family-names: Robie
+  given-names: Taylor
+- family-names: Han
+  given-names: Eric
+- family-names: Wu
+  given-names: Peng
+- family-names: Korovaiko
+  given-names: Nick
+- family-names: Ansel
+  given-names: Jason
+- family-names: Reblitz-Richardson
+  given-names: Orion
+- family-names: Chintala
+  given-names: Soumith
+message: "If you use this software, please cite it using these metadata."
+date-released: 2020-09-03
+repository-code: "https://github.com/pytorch/benchmark"