cURL error 60: SSL certificate: unable to get local issuer certificate

I am trying to send an API request using Stripe but get the error message:

cURL error 60: SSL certificate problem: unable to get local issuer certificate

This is the code I am running:

public function chargeStripe()
{
    $stripe = new Stripe;
    $stripe = Stripe::make(env('STRIPE_PUBLIC_KEY'));

    $charge = $stripe->charges()->create([
        'amount'   => 2900,
        'customer' => Input::get('stripeEmail'),
        'currency' => 'EUR',
    ]);

    return Redirect::route('step1');
}

I searched a lot on Google and lots of people are suggesting that I download this file: cacert.pem, put it somewhere and reference it in my php.ini. This is the part in my php.ini:

curl.cainfo = "C:\Windows\cacert.pem"

Yet, even after restarting my server several times and changing the path, I get the same error message.

I have the ssl_module enabled in Apache, and I have php_curl enabled in my php.ini.

I have also tried this fix: How to fix PHP CURL Error 60 SSL

Which suggests that I add these lines to my cURL options:

curl_setopt($process, CURLOPT_CAINFO, dirname(__FILE__) . '/cacert.pem');
curl_setopt($process, CURLOPT_SSL_VERIFYPEER, true);

Where do I add options to my cURL? Apparently not through the command line, since my CLI doesn’t find the command “curl_setopt”