fix license header for fix_untrained_tokens from unsloth-zoo (#2129) …

…[skip ci]

src/axolotl/core/tokenizer_utils.py

@@ -3,18 +3,12 @@
 """
 
 # Copyright 2023-present Daniel Han-Chen & the Unsloth team. All rights reserved.
+# GNU LESSER GENERAL PUBLIC LICENSE
+# Version 3, 29 June 2007
 #
-# 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.
+# Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/>
+# Everyone is permitted to copy and distribute verbatim copies
+# of this license document, but changing it is not allowed.
 
 import gc
 import itertools