To upload a theme ZIP archive, send a multipart formdata request by providing the 'Content-Type': 'multipart/form-data;' header, along with the following field encoded as FormData:
file: Blob or File The theme archive that you want to upload.
curl -X POST -F 'file=@/path/to/themes/my-theme.zip' -H "Authorization: Ghost $token" -H "Accept-Version: $version" https://{admin_domain}/ghost/api/admin/themes/upload
