Finalize a draft invoice
curl --request POST \
--url https://api.cloud.flexprice.io/v1/invoices/{id}/finalize \
--header 'x-api-key: <api-key>'{}curl --request POST \
--url https://api.cloud.flexprice.io/v1/invoices/{id}/finalize \
--header 'x-api-key: <api-key>'{}