fix Makefile

Makefile

@@ -18,17 +18,17 @@ install:
 
 .PHONY: show-version
 show-version: $(GOBIN)/gobump
-	@gobump show -r .
+	gobump show -r .
 
 $(GOBIN)/gobump:
-	@cd && go get github.com/x-motemen/gobump/cmd/gobump
+	go install github.com/x-motemen/gobump/cmd/gobump@latest
 
 .PHONY: cross
 cross: $(GOBIN)/goxz
 	goxz -n $(BIN) -pv=v$(VERSION) -build-ldflags=$(BUILD_LDFLAGS) .
 
 $(GOBIN)/goxz:
-	cd && go get github.com/Songmu/goxz/cmd/goxz
+	go install github.com/Songmu/goxz/cmd/goxz@latest
 
 .PHONY: test
 test: build
@@ -47,7 +47,7 @@ endif
 ifneq ($(shell git rev-parse --abbrev-ref HEAD),master)
 	$(error current branch is not master)
 endif
-	@gobump up -w .
+	gobump up -w .
 	git commit -am "bump up version to $(VERSION)"
 	git tag "v$(VERSION)"
 	git push origin master
@@ -58,4 +58,4 @@ upload: $(GOBIN)/ghr
 	ghr "v$(VERSION)" goxz
 
 $(GOBIN)/ghr:
-	cd && go get github.com/tcnksm/ghr
+	go install github.com/tcnksm/ghr@latest