fix: preserve toolchain flag

Author: bakito

pkg/makefile/.toolbox.mk.tpl

@@ -47,6 +47,6 @@ tb.reset:
 ## Update Tools
 .PHONY: tb.update
 tb.update: tb.reset
-	toolbox makefile {{ if $.Renovate }}--renovate {{ end }}-f $(TB_LOCALDIR)/Makefile{{- range .Tools }}{{- if not .FromToolsGo }} \
+	toolbox makefile {{ if $.Renovate }}--renovate {{ end }}{{ if $.Toolchain }}--toolchain {{ end }}-f $(TB_LOCALDIR)/Makefile{{- range .Tools }}{{- if not .FromToolsGo }} \
 		{{.Tool}}{{- end }}
 {{- end }}

testdata/.toolbox.mk.toolchain.expected

@@ -53,7 +53,7 @@ tb.reset:
 ## Update Tools
 .PHONY: tb.update
 tb.update: tb.reset
-	toolbox makefile -f $(TB_LOCALDIR)/Makefile \
+	toolbox makefile --toolchain -f $(TB_LOCALDIR)/Makefile \
 		sigs.k8s.io/controller-tools/cmd/controller-gen@github.com/kubernetes-sigs/controller-tools \
 		github.com/golangci/golangci-lint/v2/cmd/golangci-lint \
 		github.com/bakito/semver \