[FIX] account_move_line_purchase_info: Overwrite _compute_invoice to ensure invoice count consistency

account_move_line_purchase_info/migrations/13.0.1.1.0/post-migration.py

@@ -0,0 +1,13 @@
+# Copyright 2020 ForgeFlow (https://www.forgeflow.com)
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html).
+from openupgradelib import openupgrade
+
+
+@openupgrade.migrate()
+def migrate(env, version):
+    pos = (
+        env["account.move.line"]
+        .search([("purchase_id", "!=", False), ("move_id.type", "=", "entry")])
+        .mapped("purchase_id")
+    )
+    pos._compute_invoice()