Fix license: upstream is non-commercial; correct dataset card

README.md

@@ -1,5 +1,7 @@
 ---
-license: cc-by-4.0
+license: other
+license_name: cc-by-nc-3.0-igo
+license_link: https://creativecommons.org/licenses/by-nc/3.0/igo/
 pretty_name: "ESA Huygens Titan Descent"
 language:
   - en
@@ -141,4 +143,5 @@ If you find this dataset useful, please give it a ❤️ on the [dataset page](h
 
 ## License
 
-[CC-BY-4.0](https://creativecommons.org/licenses/by/4.0/)
+
+[CC-BY-NC-3.0-IGO](https://creativecommons.org/licenses/by-nc/3.0/igo/)