fix milestone format parse

conf/locale/locale_en-US.ini

@@ -406,7 +406,7 @@ milestones.title = Title
 milestones.desc = Description
 milestones.due_date = Due Date (optional)
 milestones.clear = Clear
-milestones.invalid_due_date_format = Due date format is invalid, must be 'mm/dd/year'.
+milestones.invalid_due_date_format = Due date format is invalid, must be 'year-mm-dd'.
 milestones.create_success = Milestone '%s' has been created successfully!
 milestones.edit = Edit Milestone
 milestones.edit_subheader = Use better description for milestones so people won't be confused.

routers/repo/issue.go

@@ -1033,9 +1033,9 @@ func NewMilestonePost(ctx *middleware.Context, form auth.CreateMilestoneForm) {
 	}
 
 	if len(form.Deadline) == 0 {
-		form.Deadline = "12/31/9999"
+		form.Deadline = "9999-12-31"
 	}
-	deadline, err := time.Parse("01/02/2006", form.Deadline)
+	deadline, err := time.Parse("2006-01-02", form.Deadline)
 	if err != nil {
 		ctx.Data["Err_Deadline"] = true
 		ctx.RenderWithErr(ctx.Tr("repo.milestones.invalid_due_date_format"), MILESTONE_NEW, &form)