An alternative upload provider working with latest uploadcare lib and latest  Strapi.

Set config with 

module.exports = ({ env }) => ({
    // ...
    upload: {
        config: {
      provider: 'upc',
      providerOptions: {
        public_key:"xxxxx",
        secret_key:"xxxxx",
        base_cdn_url: "https://ucarecdn.com",
      },
    },
    }
    // ...
  });