fix makefile dockerimage default tag

Makefile

@@ -1,4 +1,5 @@
 VERSION?="dev"
+TAG?="dev"
 GORELEASER_VERSION=1.18.2-pro
 
 PROJECT_ROOT=${PWD}
@@ -12,9 +13,9 @@ ifneq "$(CURRENT_GORELEASER_VERSION)" "$(GORELEASER_VERSION)"
 	@exit 1
 endif
 
-dist/docker-image.tar:
+dist/docker-image-$(TAG).tar:
 	goreleaser release --clean --skip-announce --snapshot -f .goreleaser.dev.yaml
-	docker save --output dist/docker-image.tar "kubeshop/tracetest:$(VERSION)"
+	docker save --output dist/docker-image-$(TAG).tar "kubeshop/tracetest:$(VERSION)"
 
 CLI_SRC_FILES := $(shell find cli -type f)
 dist/tracetest: goreleaser-version generate-cli $(CLI_SRC_FILES)
@@ -49,7 +50,7 @@ run: build-docker ## build and run tracetest using docker compose
 	docker compose up
 build-go: dist/tracetest dist/tracetest-server ## build all go code
 build-web: web/build ## build web
-build-docker: goreleaser-version web/build .goreleaser.dev.yaml dist/docker-image.tar ## build and tag docker image as defined in .goreleaser.dev.yaml
+build-docker: goreleaser-version web/build .goreleaser.dev.yaml dist/docker-image-$(TAG).tar ## build and tag docker image as defined in .goreleaser.dev.yaml
 
 .PHONY: generate generate-server generate-cli generate-web
 generate: generate-server generate-cli generate-web ## generate code entities from openapi definitions for all parts of the code