added RE-LICENSE_NOTE.txt (#1806)

Signed-off-by: Ken Museth <[email protected]>

Author: kmuseth

RE-LICENSE_NOTE.txt

@@ -0,0 +1,6 @@
+The following copyright holders agree that all of their contributions
+originally submitted to this project under the Mozilla Public License
+Version 2.0, are hereby relicensed to the Apache License, Version 2.0,
+and are submitted pursuant to the Developer Certificate of Origin, version 1.1:
+
+Ken Museth

README.md

@@ -35,6 +35,8 @@ Mozilla Foundation.
 The trademarks of any contributor to this project may not be used in
 association with the project without the contributor's express permission.
 
+NOTE: OpenVDB is in the process of changing its license from [Mozilla Public License Version 2.0](https://www.mozilla.org/MPL/2.0/) to [Apache License, Version 2.0](https://www.apache.org/licenses/LICENSE-2.0)! Please see the file RE-LICENSE_NOTE.txt for more details.
+
 ### Contributing
 
 OpenVDB welcomes contributions to the OpenVDB project. Please refer to the