Update en/en_US/amy/medium/MODEL_CARD

I could not find Amy in mimic 3, I found her in mimic 2, and the license is Apache-2.0, I think it's helpful to have that in the model card instead of redirecting?

en/en_US/amy/medium/MODEL_CARD

@@ -7,8 +7,8 @@
 
 ## Dataset
 
-* URL: https://github.com/MycroftAI/mimic3-voices
-* License: See URL
+* URL: https://github.com/MycroftAI/mimic2
+* License: Apache-2.0
 
 ## Training