[OU-IMP] project: merge project_milestone

Parts of the project_milestone feature are merged into the `project`
module and another part of the feature are moved to the
`project_task_milestone` module.

openupgrade_scripts/apriori.py

@@ -19,6 +19,7 @@
     "website_sale_attribute_filter_order": "website_sale_product_attribute_filter_order",
     # OCA/project
     "project_category": "project_type",
+    "project_milestone": "project_task_milestone",
     "project_stage_state": "project_task_stage_state",
     "sale_project_service_tracking_copy_tasks": "sale_project_copy_tasks",
     # OCA/sale-promotion

openupgrade_scripts/scripts/project/15.0.1.2/pre-migration.py

@@ -60,9 +60,21 @@ def adapt_project_task_dependency(env):
     )
 
 
+def rename_project_milestone_target_date(env):
+    """If project_milestone is installed then rename column target_date
+    to deadline.
+    """
+    if openupgrade.column_exists(env.cr, "project_milestone", "target_date"):
+        openupgrade.rename_columns(
+            env.cr,
+            {"project_milestone": [("target_date", "deadline")]},
+        )
+
+
 @openupgrade.migrate()
 def migrate(env, version):
     openupgrade.rename_columns(env.cr, _column_renames)
     adapt_project_task_dependency(env)
     fill_project_project_allow_task_dependencies(env)
     fill_project_project_last_update_status(env)
+    rename_project_milestone_target_date(env)