chore: use GitHub Actions.

Makefile

@@ -2,19 +2,21 @@
 
 TAG_NAME := $(shell git tag -l --contains HEAD)
 
+IMAGE_NAME := traefik/whoami
+
 default: check test build
 
+build:
+	CGO_ENABLED=0 go build -a --trimpath --installsuffix cgo --ldflags="-s" -o whoami
+
 test:
 	go test -v -cover ./...
 
-build:
-	CGO_ENABLED=0 go build -a --installsuffix cgo --ldflags="-s" -o whoami
-
-image:
-	docker build -t traefik/whoami .
-
 check:
 	golangci-lint run
 
+image:
+	docker build -t $(IMAGE_NAME) .
+
 publish-images:
-	seihon publish -v "$(TAG_NAME)" -v "latest" --image-name traefik/whoami --dry-run=false
+	seihon publish -v "$(TAG_NAME)" -v "latest" --image-name $(IMAGE_NAME) --dry-run=false