Document pyRiemann 0.9 and numpy 2.0 compatibility update in changelog (#821)

* Initial plan

* Document pyRiemann 0.9 and numpy 2.0 compatibility update

Co-authored-by: bruAristimunha <42702466+bruAristimunha@users.noreply.github.com>

* Update whats_new.rst

Signed-off-by: gcattan <gcattan@hotmail.fr>

---------

Signed-off-by: gcattan <gcattan@hotmail.fr>
Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: bruAristimunha <42702466+bruAristimunha@users.noreply.github.com>
Co-authored-by: gcattan <gcattan@hotmail.fr>
Co-authored-by: Pierre Guetschel <25532709+PierreGtch@users.noreply.github.com>

Author: 4 people

docs/source/whats_new.rst

@@ -19,6 +19,7 @@ Develop branch  - 1.4  (dev)
 --------------------------------------
 Enhancements
 ~~~~~~~~~~~~
+- Update to pyRiemann 0.9 and numpy 2.0 for improved compatibility (:gh:`789` by `Gregoire Cattan`_ and `Bruno Aristimunha`_)
 - Adding :class:`moabb.datasets.Kojima2024A` (:gh:`807` by `Simon Kojima`_)
 - Adding :class:`moabb.datasets.Kojima2024B` (:gh:`806` by `Simon Kojima`_)
 - Add new dataset :class:`moabb.datasets.BNCI2003_IVa` dataset (:gh:`811` by `Griffin Keeler`_)