Merge branch 'update-codeowners-scss' into 'master'

Update CODEOWNERS for FE and .scss

See merge request gitlab-org/gitlab-ce!21913

.gitlab/CODEOWNERS

@@ -6,7 +6,8 @@
 /doc/ @axil @marcia
 
 # Frontend maintainers should see everything in `app/assets/`
-app/assets/ @annabeldunstone @ClemMakesApps @fatihacet @filipa @iamphill @mikegreiling @timzallmann
+app/assets/ @ClemMakesApps @fatihacet @filipa @iamphill @mikegreiling @timzallmann
+*.scss @annabeldunstone @ClemMakesApps @fatihacet @filipa @iamphill @mikegreiling @timzallmann
 
 # Someone from the database team should review changes in `db/`
 db/ @abrandl @NikolayS