kartongips: switch default diff behaviour to subset, nag users

Change-Id: I998cdf7e693f6d1ce86c7ea411f47320d72a5906
diff --git a/cluster/tools/kartongips/cmd/BUILD.bazel b/cluster/tools/kartongips/cmd/BUILD.bazel
index dee1b41..a75ee83 100644
--- a/cluster/tools/kartongips/cmd/BUILD.bazel
+++ b/cluster/tools/kartongips/cmd/BUILD.bazel
@@ -19,6 +19,7 @@
         "//cluster/tools/kartongips/utils:go_default_library",
         "@com_github_genuinetools_reg//registry:go_default_library",
         "@com_github_google_go_jsonnet//:go_default_library",
+        "@com_github_mattn_go_isatty//:go_default_library",
         "@com_github_sirupsen_logrus//:go_default_library",
         "@com_github_spf13_cobra//:go_default_library",
         "@io_k8s_apimachinery//pkg/api/meta:go_default_library",