update release notes

Author: FabianHofmann

doc/release_notes.rst

@@ -3,6 +3,10 @@ Release Notes
 
 Upcoming Version
 ----------------
+
+Version 0.5.1
+--------------
+
 **Deprecations**
 
 * Renamed `expression.empty()` to `expression.empty` to align with the use of empty in
@@ -17,6 +21,10 @@ Upcoming Version
 * Added `align` function as a wrapper around :func:`xr.align`.
 * Avoid allocating a floating license for COPT during the initial solver check
 
+**Bug fixes**
+
+* Ensure compatibility with xarray >= v2025.03.00
+
 Version 0.5.0
 --------------