Make keyring use optional about sendgridr

[mrchypark]

Good idea! I'll be working on it soon.

[agronomofiorentini]

I agree with @vituri, it would be wonderful if you can use auth_set or auth_check function with api key defined inside .Renviron so we can automatically send emails in shinyapps without using keyring R package

[mrchypark]

I will add apikey param on auth_set() for use Sys.getenv("SENDGRID_API"). auth_set() will work like before without param. But with param like auth_set(Sys.getenv("SENDGRID_API")), use input without prompt.

[agronomofiorentini]

Thanks @mrchypark.

Let know us when is done and we will test it and report to you if is working.

Thanks again for the effort.