Copy code from Bert to Roberta and add safeguard script (#7219)

* Copy code from Bert to Roberta and add safeguard script

* Fix docstring

* Comment code

* Formatting

* Update src/transformers/modeling_roberta.py

Co-authored-by: Lysandre Debut <lysandre@huggingface.co>

* Add test and fix bugs

* Fix style and make new comand

Co-authored-by: Lysandre Debut <lysandre@huggingface.co>

utils/check_repo.py

@@ -1,3 +1,18 @@
+# coding=utf-8
+# Copyright 2020 The HuggingFace Inc. team.
+#
+# 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.
+
 import importlib
 import inspect
 import os