Fix `license` metadata

We recently updated the datasets metadata for consistency with other repo types (models & spaces)

Thanks! 🙏

README.md

@@ -3,7 +3,7 @@ annotations_creators:
 - found
 language_creators:
 - expert-generated
-languages:
+language:
 - cs
 - de
 - en
@@ -24,7 +24,7 @@ languages:
 - ta
 - tr
 - zh
-licenses:
+license:
 - unknown
 multilinguality:
 - multilingual