update Makefile with generate steps for yarn

Signed-off-by: Jörn Friedrich Dreyer <jfd@butonic.de>

konnectd/Makefile

@@ -63,6 +63,8 @@ sync:
 clean:
 	go clean -i ./...
 	rm -rf $(BIN) $(DIST)
+	rm -rf node_modules
+	rm -rf assets/identifier
 
 .PHONY: fmt
 fmt:
@@ -84,12 +86,16 @@ lint:
 generate: assets
 	go generate $(GENERATE)
 
-.PHONY: assets
-assets:
-	mkdir -p assets/identifier/static
+assets: assets/identifier/index.html
 	curl -o assets/identifier/static/logo.svg ${LOGO_URL}
 	curl -o assets/identifier/static/favicon.ico ${FAVICON_URL}
 
+assets/identifier/index.html: node_modules
+	yarn build
+
+node_modules:
+	yarn install
+
 .PHONY: changelog
 changelog:
 	go run github.com/restic/calens >| CHANGELOG.md