docs: update Makefile help (#505)

Add help messages for build and build-goreleaser

Signed-off-by: Kairo Araujo <kairo.araujo@testifysec.com>

Makefile

@@ -8,10 +8,10 @@ BUILDFLAGS := -trimpath
 clean: ## Clean the binary directory
 	rm -rf $(BINDIR)
 
-build:
+build: ## Build the binary
 	CGO_ENABLED=0 go build $(BUILDFLAGS) -o $(BINDIR)/$(BINNAME) ./main.go
 
-build-goreleaser:
+build-goreleaser: ## Build the binary using goreleaser
 	goreleaser build --snapshot --clean
 
 vet: ## Run go vet