fix: update author image URLs to use Twitter profile images (#485)

Author: jiashengguo

blog/authors.yml

@@ -3,10 +3,11 @@ yiming:
     email: yiming@whimslab.io
     url: https://twitter.com/ymcao9
     title: Co-founder of ZenStack
-    image_url: https://res.cloudinary.com/practicaldev/image/fetch/s--3oZCIpBP--/c_fill,f_auto,fl_progressive,h_320,q_auto,w_320/https://dev-to-uploads.s3.amazonaws.com/uploads/user/profile_image/907052/052134eb-bb88-4c78-9d13-4865051807aa.png
+    image_url: https://pbs.twimg.com/profile_images/1625096006177292289/XSHuh6sj_400x400.png
 jiasheng:
     name: Jiasheng
     email: jiasheng@whimslab.io
     url: https://twitter.com/jiashenggo
     title: Co-founder of ZenStack
-    image_url: https://res.cloudinary.com/practicaldev/image/fetch/s--DSfEP93t--/c_fill,f_auto,fl_progressive,h_320,q_auto,w_320/https://dev-to-uploads.s3.amazonaws.com/uploads/user/profile_image/964530/a5f89e84-78d9-40db-aa1f-0cffc766d88a.jpg
+    image_url: https://pbs.twimg.com/profile_images/1590705781279789056/zH5HFsNx_400x400.jpg
+