docs: add commit hash to setup-pixi

Co-authored-by: Bryce Mecum <[email protected]>

Author: esadek

.github/workflows/publish_docs.yml

@@ -28,7 +28,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - uses: prefix-dev/setup-pixi@v0.9.3
+      - uses: prefix-dev/setup-pixi@82d477f15f3a381dbcc8adc1206ce643fe110fb7
         with:
           pixi-version: v0.59.0
           cache: true