build: skip admin and client generation on windows

makefile

@@ -20,16 +20,23 @@ endif
 
 .PHONY: admin
 admin:
+ifeq ($(OS),Windows_NT)
+	@echo "Please generate ./admin/ on macOS or Linux, currently unsupported on windows."
+else
 # Versions from https://github.com/OpenAPITools/openapi-generator/releases
 	@chmod +x ./openapi-generator
 	@rm -rf ./admin
 	OPENAPI_GENERATOR_VERSION=4.3.0 ./openapi-generator generate --package-name admin -i openapi-admin.yaml -g go -o ./admin
 	rm -f admin/go.mod admin/go.sum
 	go fmt ./...
 	go test ./admin
+endif
 
 .PHONY: client
 client:
+ifeq ($(OS),Windows_NT)
+	@echo "Please generate ./client/ on macOS or Linux, currently unsupported on windows."
+else
 # Versions from https://github.com/OpenAPITools/openapi-generator/releases
 	@chmod +x ./openapi-generator
 	@rm -rf ./client
@@ -38,6 +45,7 @@ client:
 	go fmt ./...
 	go build github.com/moov-io/customers/client
 	go test ./client
+endif
 
 .PHONY: clean
 clean: