Update pixi on CI

Author: emilk

.github/workflows/cpp.yml

@@ -17,7 +17,7 @@ jobs:
 
       - uses: prefix-dev/[email protected]
         with:
-          pixi-version: v0.26.1
+          pixi-version: v0.41.4
           cache: true
 
       - run: pixi run build