fix pixi CI

Author: facontidavide

.github/workflows/pixi.yaml

@@ -18,7 +18,6 @@ jobs:
     steps:
       # Pixi is the tool used to create/manage conda environment
       - uses: actions/checkout@v6
-      - uses: prefix-dev/setup-pixi@v0.8.1
       - uses: prefix-dev/setup-pixi@v0.9.3
         with:
           pixi-version: v0.40.3