Fix CECILL-B licence link

ping @inria everyone is having problems reaching https://cecill.info/licences/Licence_CeCILL-B_V1-en.txt one way or another

README.md

@@ -1520,7 +1520,7 @@ See also [Documentation Generators](#documentation-generators), [Wikimatrix](htt
 - `CC-BY-SA-4.0` - [Creative Commons Attribution-ShareAlike 4.0 International License](https://creativecommons.org/licenses/by-sa/4.0/)
 - `CC0-1.0` - [Public Domain](https://creativecommons.org/about/cc0/)
 - `CDDL-1.0` - [Common Development and Distribution License](https://opensource.org/licenses/CDDL-1.0)
-- `CECILL-B` - [CEA CNRS INRIA Logiciel Libre](https://www.cecill.info/licences/Licence_CeCILL-B_V1-en.txt)
+- `CECILL-B` - [CEA CNRS INRIA Logiciel Libre](https://spdx.org/licenses/CECILL-B.html)
 - `CPAL-1.0` - [Common Public Attribution License Version 1.0](http://opensource.org/licenses/CPAL-1.0)
 - `DPL` - [Devblocks Public License 1.0](https://cerb.ai/license/)
 - `ECL-2.0` - [Educational Community License, Version 2.0 ](http://opensource.org/licenses/ECL-2.0)