nginx做反向代理时如何只缓存指定扩展名的文件

location ~ ^/v3 {
    proxy_pass https://api.nuget.org;
    location ~ .nupkg$ {
        proxy_pass https://api.nuget.org;
        proxy_cache nuget-cache;
        proxy_cache_valid 2400h;
    }
}