Disable vendoring

Makefile

@@ -1,5 +1,5 @@
-build: vendor
-	CGO_ENABLED=0 go build -mod=vendor -v -o bin/fake-smtp ./cmd/fake-smtp
+build:
+	CGO_ENABLED=0 go build -v -o bin/fake-smtp ./cmd/fake-smtp
 
 docker-image:
 	docker build \
@@ -33,9 +33,6 @@ release: dist
 dist:
 	npm run build
 
-vendor:
-	go mod vendor
-
 tidy:
 	go mod tidy