fix LICENSE

- the license text is not under zib copyright
- use exact version of https://www.apache.org/licenses/LICENSE-2.0.txt
  (so, e.g., github will recognize the license)

LICENSE

@@ -1,7 +1,3 @@
-Copyright (c) 2002-2025 Zuse Institute Berlin (ZIB)
-
-Licensed under the Apache License, Version 2.0 (the "License");
-the license terms are reproduced below.
 
                                  Apache License
                            Version 2.0, January 2004
@@ -179,3 +175,28 @@ the license terms are reproduced below.
       of your accepting any such warranty or additional liability.
 
    END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
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+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
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+
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+
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