Change prettier package source to yarnpkg because the extend artifact repository is not available. This could alternatively be made public, but since none of the other packages reference the artifact repository, this seems accidental.

Author: mslosarek

Diff for: yarn.lock

@@ -3395,7 +3395,7 @@ prettier-linter-helpers@^1.0.0:
 
 [email protected]:
   version "2.1.1"
-  resolved "https://extend-159581800400.d.codeartifact.us-east-1.amazonaws.com:443/npm/extend-npm/prettier/-/prettier-2.1.1.tgz#d9485dd5e499daa6cb547023b87a6cf51bee37d6"
+  resolved "https://registry.yarnpkg.com/prettier/-/prettier-2.1.1.tgz#d9485dd5e499daa6cb547023b87a6cf51bee37d6"
   integrity sha512-9bY+5ZWCfqj3ghYBLxApy2zf6m+NJo5GzmLTpr9FsApsfjriNnS2dahWReHMi7qNPhhHl9SYHJs2cHZLgexNIw==
 
 pretty-format@^24.9.0: