[FIX] stock_picking_invoicing: Dropshipping Case.

Author: mbcosta

Diff for: stock_picking_invoicing/wizards/stock_invoice_onshipping.py

@@ -18,6 +18,7 @@
     ("outgoing", "internal", "customer"): "out_invoice",
     ("incoming", "customer", "internal"): "out_refund",
     ("incoming", "supplier", "internal"): "in_invoice",
+    ("incoming", "supplier", "customer"): "in_invoice",
     ("outgoing", "internal", "supplier"): "in_refund",
     ("incoming", "transit", "internal"): "in_invoice",
     ("outgoing", "transit", "supplier"): "in_refund",