Create payment session

curl --request POST \
  --url https://api.sprintcheckout.com/api/checkout/v2/payment_session \
  --header 'Content-Type: application/json' \
  --header 'X-SC-ApiKey: <x-sc-apikey>' \
  --data '{
  "orderType": "STATIC",
  "amount": 100.5,
  "minAmount": 100.5,
  "editable": true,
  "currency": "USD",
  "orderId": "inv-00010",
  "successUrl": "<string>",
  "cancelUrl": "<string>"
}'

{
  "sessionId": "<string>",
  "redirectUrl": "<string>"
}