add missing Apache License to ChangeLog.md
diff --git a/ChangeLog.md b/ChangeLog.md
index 9a8e701..8f69a2c 100644
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,3 +1,22 @@
+```
+Licensed to the Apache Software Foundation (ASF) under one
+or more contributor license agreements.  See the NOTICE file
+distributed with this work for additional information
+regarding copyright ownership.  The ASF licenses this file
+to you 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.
+```
+
 **2019-10-12  Juan Pablo Santos (juanpablo AT apache DOT org)**
 
 * _2.11.0-M6-git-02_