Update GL headers

thirdparty/include/GLES3/gl3platform.h

@@ -2,19 +2,8 @@
 #define __gl3platform_h_
 
 /*
-** Copyright (c) 2017 The Khronos Group Inc.
-**
-** 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 2017-2020 The Khronos Group Inc.
+** SPDX-License-Identifier: Apache-2.0
 */
 
 /* Platform-specific types and definitions for OpenGL ES 3.X  gl3.h