fix Dockerfile context bug

Dockerfile

@@ -1,6 +1,6 @@
 
 ARG GOLANG_IMAGE=golang:1.16.5
-FROM ${GOLANG_IMAGE} as binary_tools_context
+FROM ${GOLANG_IMAGE} as build_context
 
 ENV OUTDIR=/out
 RUN mkdir -p ${OUTDIR}/usr/local/bin/
@@ -9,15 +9,14 @@ WORKDIR /workspace
 ADD . /workspace/
 
 RUN make all
-RUN mv /workspace/bin/{server,client,kubectl-kn} ${OUTDIR}/usr/local/bin/
+RUN mv /workspace/bin/* ${OUTDIR}/usr/local/bin/
 
 ##############
 # Final image
 #############
 
 FROM alpine:3.11 
 
-COPY --from=base_os_context /out/ /
 COPY --from=build_context /out/ /
 
 WORKDIR /

cmd/client/main.go

@@ -16,7 +16,8 @@ func main() {
 	clientOptions := app.NewClientOptions()
 
 	command := &cobra.Command{
-		Use: "Kunnel",
+		Use:  "client",
+		Long: "A tool for tunnel local service.",
 		RunE: func(cmd *cobra.Command, args []string) error {
 			local, err := utils.NewLocal(clientOptions.Local)
 			if err != nil {

cmd/kn/main.go

@@ -23,7 +23,8 @@ func main() {
 	knOptions := app.NewKnOptions()
 
 	knCommand := &cobra.Command{
-		Use: "kn is a kubectl plugin to proxy kubernetes service outside the cluster.",
+		Use:  "kubectl-kn",
+		Long: "kn is a kubectl plugin to proxy kubernetes service outside the cluster.",
 		RunE: func(cmd *cobra.Command, args []string) error {
 			if len(knOptions.Service) == 0 {
 				return fmt.Errorf("service not provided")