Pin drf-yasg to make api-test pass (#15887)

Ping drf-yasg to make api-test pass

Author: AlanCoding

requirements/requirements_dev.txt

@@ -2,7 +2,7 @@ build
 coreapi
 django-debug-toolbar==3.2.4
 django-test-migrations
-drf-yasg
+drf-yasg<1.21.10  # introduces new DeprecationWarning that is turned into error
 # pprofile - re-add once https://github.com/vpelletier/pprofile/issues/41 is addressed
 ipython>=7.31.1 # https://github.com/ansible/awx/security/dependabot/30
 unittest2