Add multilingual to the language tag

Hi! A PR to add multilingual to the language tag to improve the referencing.

README.md

@@ -1,12 +1,11 @@
 ---
-language: 
+language:
 - zh
 - en
-
+- multilingual
+license: cc-by-4.0
 tags:
 - translation
-
-license: cc-by-4.0
 ---
 
 ### zho-eng
@@ -87,7 +86,7 @@ Further details about the dataset for this model can be found in the OPUS readme
 ```bibtex
 @InProceedings{TiedemannThottingal:EAMT2020,
   author = {J{\"o}rg Tiedemann and Santhosh Thottingal},
-  title = {{OPUS-MT} — {B}uilding open translation services for the {W}orld},
+  title = {{OPUS-MT} � {B}uilding open translation services for the {W}orld},
   booktitle = {Proceedings of the 22nd Annual Conferenec of the European Association for Machine Translation (EAMT)},
   year = {2020},
   address = {Lisbon, Portugal}