Fix broken migration on webhook (#13911)

* Fix broken migration on webhook

* Fix lint

Co-authored-by: John Olheiser <john.olheiser@gmail.com>

models/migrations/v162.go

@@ -0,0 +1,59 @@
+// Copyright 2020 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package migrations
+
+import (
+	"xorm.io/xorm"
+)
+
+func convertWebhookTaskTypeToString(x *xorm.Engine) error {
+	const (
+		GOGS int = iota + 1
+		SLACK
+		GITEA
+		DISCORD
+		DINGTALK
+		TELEGRAM
+		MSTEAMS
+		FEISHU
+		MATRIX
+	)
+
+	var hookTaskTypes = map[int]string{
+		GITEA:    "gitea",
+		GOGS:     "gogs",
+		SLACK:    "slack",
+		DISCORD:  "discord",
+		DINGTALK: "dingtalk",
+		TELEGRAM: "telegram",
+		MSTEAMS:  "msteams",
+		FEISHU:   "feishu",
+		MATRIX:   "matrix",
+	}
+
+	type Webhook struct {
+		Type string `xorm:"char(16) index"`
+	}
+	if err := x.Sync2(new(Webhook)); err != nil {
+		return err
+	}
+
+	for i, s := range hookTaskTypes {
+		if _, err := x.Exec("UPDATE webhook set type = ? where hook_task_type=?", s, i); err != nil {
+			return err
+		}
+	}
+
+	sess := x.NewSession()
+	defer sess.Close()
+	if err := sess.Begin(); err != nil {
+		return err
+	}
+	if err := dropTableColumns(sess, "webhook", "hook_task_type"); err != nil {
+		return err
+	}
+
+	return sess.Commit()
+}