Fix typing extension import for tests (#4190)

I'm getting a bunch of test errors and it's annoying. Based off of

https://github.com/huggingface/huggingface_hub/pull/453/files

(which is the solution to huggingface/huggingface_hub#452 )

it seems like changing this version should be what we need...

requirements.txt

@@ -46,7 +46,7 @@ tokenizers>=0.8.0
 torchtext>=0.5.0
 tornado==6.0.4
 tqdm~=4.62.1
-typing-extensions==3.7.4.1
+typing-extensions==3.7.4.3
 Unidecode==1.1.1
 urllib3>=1.26.5
 websocket-client==0.56.0