Just found this while trying to fix a proxy related issue I was having, but this seems an easy fix.
In the error message:
Run-time warning: curl_setopt_array(): Array keys must be CURLOPT constants or equivalent integer values
In your code:
'curl' => [ 'CURLOPT_PROXY' => '*.*.*.*', 'CURLOPT_PROXYPORT' => 80, 'CURLOPT_PROXYUSERPWD' => '*:*', ],
You have made the constants strings, so therefore they do not pass as valid keys.