Warn agaist `libcurl-minimal` in RHEL-9 / RockyLinux 9

[jeroen]

See also: jeroen/curl#350

It turns out RHEL 9 now has two different versions of libcurl, and the default one does not enable smpt. Users might then get an error like mail_rcpt: An unknown option was passed in to libcurl.

The solution is for the user to swap out libcurl-minimal for the normal libcurl like so:

sudo dnf install -y libcurl --allowerasing

There is no need to rebuild the R package, this is purely a runtime security restriction.

Perhaps blastula should warn for this by checking if smtp is enabled: 'smtp' %in% curl::curl_version()$protocols