Fix bibtex citation in README.md (#11244)

I am getting an error from `biblatex` that the entry has too many commas.

Author: khatchad

README.md

@@ -121,8 +121,8 @@ If you use TensorFlow Model Garden in your research, please cite this repository
 
 ```
 @misc{tensorflowmodelgarden2020,
-  author = {Hongkun Yu, Chen Chen, Xianzhi Du, Yeqing Li, Abdullah Rashwan, Le Hou, Pengchong Jin, Fan Yang,
-            Frederick Liu, Jaeyoun Kim, and Jing Li},
+  author = {Hongkun Yu and Chen Chen and Xianzhi Du and Yeqing Li and Abdullah Rashwan and Le Hou and Pengchong Jin and Fan Yang
+            and Frederick Liu and Jaeyoun Kim and Jing Li},
   title = {{TensorFlow Model Garden}},
   howpublished = {\url{https://github.com/tensorflow/models}},
   year = {2020}