ci: add missing checkout

Author: cmdoret

.github/workflows/build-images-manifests.yml

@@ -60,6 +60,9 @@ jobs:
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3
 
+      - name: Checkout current repo
+        uses: actions/checkout@v5
+
       - uses: ./.github/actions/setup-nix
 
       - name: Create all multi-platform manifests