[Doc] Add comments for PPSeg && PPClas (#396)

* Add comment for PPSeg && PPClas

* Update main_page.md

fastdeploy/vision/segmentation/ppseg/model.cc

@@ -1,3 +1,17 @@
+// Copyright (c) 2022 PaddlePaddle 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.
+
 #include "fastdeploy/vision/segmentation/ppseg/model.h"
 #include "fastdeploy/vision.h"
 #include "fastdeploy/vision/utils/utils.h"