[pkg] target to build windows pkg in container

docker/Makefile

@@ -10,5 +10,14 @@ prune:
 	docker system prune
 login:
 	docker login $(REGISTRY)
+package_win:
+	docker run \
+	    -e XBUILD=win \
+	    -e PROVIDER=riseup \
+	    -v `python3 -c 'import os; print(os.path.abspath(".."))'`:/bitmask-vpn.orig \
+	    --cpus="4" \
+	    -it --rm \
+	    $(REGISTRY)/$(IMAGE):latest  \
+	    /builder.sh
 shell:
 	docker run -v `python3 -c 'import os; print(os.path.abspath(".."))'`:/bitmask-vpn.orig -it --rm $(REGISTRY)/$(IMAGE):latest  /bin/bash