ci: let a failed SBOM stop the release instead of shipping without one

Author: kobihikri

.github/workflows/build.yml

@@ -557,7 +557,6 @@ jobs:
       - name: Generate checksum file
         run: cd dist && sha256sum * > "k6-${VERSION}-checksums.txt"
       - name: Anchore SBOM Action
-        continue-on-error: true
         uses: anchore/sbom-action@e22c389904149dbc22b58101806040fa8d37a610 # v0.24.0
         with:
           artifact-name: k6-${{ env.VERSION }}-spdx.json