Fix trailing , in generation_config.json

That trailing , is causing a JSON parsing problem when loading with transformers library.

generation_config.json

@@ -3,5 +3,5 @@
   "bos_token_id": 0,
   "eos_token_id": 0,
   "pad_token_id": 0,
-  "transformers_version": "4.41.0.dev0",
+  "transformers_version": "4.41.0.dev0"
 }