expand 5k scale pool (kubernetes#8918)

Author: upodroid

kubernetes/gke-prow-build/prow/boskos-resources-configmap.yaml

@@ -211,10 +211,9 @@ data:
       type: scalability-project
     - names:
       - k8s-infra-e2e-scale-5k-project
-      # uncomment after the quotas have been bumped
-      # - k8s-infra-e2e-boskos-scale-28
-      # - k8s-infra-e2e-boskos-scale-29
-      # - k8s-infra-e2e-boskos-scale-30
+      - k8s-infra-e2e-boskos-scale-28
+      - k8s-infra-e2e-boskos-scale-29
+      - k8s-infra-e2e-boskos-scale-30
       state: dirty
       type: scalability-scale-project
     - names: