Returns a list of all payment requests in your Plane workspace.
pending, approved, declined or
processed.starting_after is an object ID that defines your place in the
list. For instance, if you make a list request and receive 100 objects, ending with obj_foo,
your subsequent call can include starting_after=obj_foo in order to fetch the next page of the
list.ending_before=obj_bar in order to fetch the previous page of the
list.payment_requests property that contains an array of Payment Request objects.