update makefile

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

Makefile

@@ -31,7 +31,7 @@ all: build
 
 .PHONY: fmt-check
 fmt-check:
- 	# get all go files and run go fmt on them
+	# get all go files and run go fmt on them
 	@diff=$$($(GOFMT) -d $(GOFILES)); \
 	if [ -n "$$diff" ]; then \
 		echo "Please run 'make fmt' and commit the result:"; \