Changes to Billing Events

the endpoint scheme security billingApiKey was added to the API

the endpoint scheme security adminApiKey was removed from the API

added the new optional query request parameter source

added the new optional query request parameter tag

added the optional property billing_events/items/tags to the response with the 200 status

response property billing_events/items/output_units deprecated

added the required property billing_events/items/quantity to the response with the 200 status

added the required property billing_events/items/unit to the response with the 200 status