Update README.md

The table reports `google/t5-large-ssm-tqa` rather than `google/t5-11b-ssm-tqa`

README.md

@@ -26,7 +26,7 @@ Authors: *Adam Roberts, Colin Raffel, Noam Shazeer*
 
 |Id | link | Exact Match  |
 |---|---|---|
-|**T5-11b**|**https://huggingface.co/google/t5-large-ssm-tqa**|**60.5**|
+|**T5-11b**|**https://huggingface.co/google/t5-11b-ssm-tqa**|**60.5**|
 |T5-xxl|https://huggingface.co/google/t5-xxl-ssm-tqa|61.6|
 
 ## Usage