chore: add action checkout

Author: ethanholz

.github/workflows/generate_sbom.yaml

@@ -10,6 +10,7 @@ jobs:
     name: Generate Jobs
     runs-on: ubuntu-latest
     steps:
+      - uses: actions/checkout@v6
       - name: Install Pixi
         uses: prefix-dev/setup-pixi@v0.9.6
         with: