fix: add deprecated warnings to kind and api fields

api/types/kustomization.go

@@ -191,6 +191,8 @@
 	deprecatedPatchesStrategicMergeMessage     = "# Warning: 'patchesStrategicMerge' is deprecated. Please use 'patches' instead." + " " + deprecatedWarningToRunEditFix
 	deprecatedVarsMessage                      = "# Warning: 'vars' is deprecated. Please use 'replacements' instead." + " " + deprecatedWarningToRunEditFixExperimential
 	deprecatedCommonLabelsWarningMessage       = "# Warning: 'commonLabels' is deprecated. Please use 'labels' instead." + " " + deprecatedWarningToRunEditFix
+	deprecationWarningKind                     = "# Warning: 'kind' field is required in future releases. Please set it explicitly."
+	deprecationWarningAPIVersion               = "# Warning: 'apiVersion' field is required in future releases. Please set it explicitly."
 )
 
 // CheckDeprecatedFields check deprecated field is used or not.
@@ -222,10 +224,13 @@
 // moving content of deprecated fields to newer
 // fields.
 func (k *Kustomization) FixKustomization() {
+	var warnings []string
 	if k.Kind == "" {
+		warnings = append(warnings, deprecationWarningKind)
 		k.Kind = KustomizationKind
 	}
 	if k.APIVersion == "" {
+		warnings = append(warnings, deprecationWarningAPIVersion)
 		if k.Kind == ComponentKind {
 			k.APIVersion = ComponentVersion
 		} else {