fix: Support Telegram Notification provider (#2225)

* fear: support telegram provider

* fix: fix telegram logo

* fix: fix telegram bot package

* Update telegram.go

* Update notification.go

---------

Co-authored-by: hsluoyz <hsluoyz@qq.com>

notification/provider.go

@@ -0,0 +1,25 @@
+// Copyright 2023 The Casdoor Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package notification
+
+import "github.com/nikoksr/notify"
+
+func GetNotificationProvider(typ string, appId string, receiver string) (notify.Notifier, error) {
+	if typ == "Telegram" {
+		return NewTelegramProvider(appId, receiver)
+	}
+
+	return nil, nil
+}