RT#912296/ISTWCMS-2750: Update to uw_ct_service 7.x-2.21

uw_base_profile.make

@@ -1858,7 +1858,7 @@ projects[uw_ct_promo_item][subdir] = "features"
 projects[uw_ct_service][type] = "module"
 projects[uw_ct_service][download][type] = "git"
 projects[uw_ct_service][download][url] = "https://git.uwaterloo.ca/wcms/uw_ct_service.git"
-projects[uw_ct_service][download][tag] = "7.x-2.20"
+projects[uw_ct_service][download][tag] = "7.x-2.21"
 projects[uw_ct_service][subdir] = "features"
 
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