Values:
LINE_ITEM_CHANGE_TYPE_UNSPECIFIED (0):
Sentinel value. Do not use.
LINE_ITEM_CHANGE_TYPE_CREATE (1):
The change is to create a new line item.
LINE_ITEM_CHANGE_TYPE_UPDATE (2):
The change is to update an existing line
item.
LINE_ITEM_CHANGE_TYPE_CANCEL (3):
The change is to cancel an existing line
item.
LINE_ITEM_CHANGE_TYPE_REVERT_CANCELLATION (4):
The change is to revert a cancellation.
