refactor: use strings.Builder to improve performance

Signed-off-by: promalert <promalert@outlook.com>

pkg/action/uninstall.go

@@ -242,9 +242,9 @@ func (u *Uninstall) deleteRelease(rel *release.Release) (kube.ResourceList, stri
 	}
 
 	filesToKeep, filesToDelete := filterManifestsToKeep(files)
-	var kept string
+	var kept strings.Builder
 	for _, f := range filesToKeep {
-		kept += "[" + f.Head.Kind + "] " + f.Head.Metadata.Name + "\n"
+		fmt.Fprintf(&kept, "[%s] %s\n", f.Head.Kind, f.Head.Metadata.Name)
 	}
 
 	var builder strings.Builder
@@ -259,7 +259,7 @@ func (u *Uninstall) deleteRelease(rel *release.Release) (kube.ResourceList, stri
 	if len(resources) > 0 {
 		_, errs = u.cfg.KubeClient.Delete(resources, parseCascadingFlag(u.DeletionPropagation))
 	}
-	return resources, kept, errs
+	return resources, kept.String(), errs
 }
 
 func parseCascadingFlag(cascadingFlag string) v1.DeletionPropagation {