Use the kpt-reviewers team for single-assignment

Avoid assigning to everyone (as then nobody feels responsible); assign
to one person from the kpt-reviewers team.

CODEOWNERS

@@ -1,18 +1,15 @@
 # Generally we are following a permissive policy of code ownership
-# Some people have asked for only minimal permissions to avoid notification spam: @bgrant0607
-
-# Default, unless something takes precedence below
-* @droot @justinsb @mortent @natasha41575 @yuwenma
+# We use the @GoogleContainerTools/kpt-reviewers group so that we can assign a single person to each PR.
 
 # Docs
-/site @bgrant0607 @droot @justinsb @mortent @natasha41575 @yuwenma
+/site @GoogleContainerTools/kpt-reviewers
 # These packages are referenced in docs.
-/package-examples/nginx/ @droot @justinsb @mortent @natasha41575 @yuwenma
-/package-examples/wordpress/ @droot @justinsb @mortent @natasha41575 @yuwenma
+/package-examples/nginx/ @GoogleContainerTools/kpt-reviewers
+/package-examples/wordpress/ @GoogleContainerTools/kpt-reviewers
 
 # Schemas changes additional scrutiny.
-/pkg/api @droot @justinsb @mortent @natasha41575 @yuwenma
+/pkg/api @GoogleContainerTools/kpt-reviewers
 
 # These tests enforce the behavior for fn
-kpt/e2e/testdata/fn-render @droot @justinsb @mortent @natasha41575 @yuwenma
-kpt/e2e/testdata/fn-eval @droot @justinsb @mortent @natasha41575 @yuwenma
+kpt/e2e/testdata/fn-render @GoogleContainerTools/kpt-reviewers
+kpt/e2e/testdata/fn-eval @GoogleContainerTools/kpt-reviewers