add firecracker version to versions.json
add firecracker version to versions.json

cf-unik/unik,cf-unik/unik,cf-unik/unik,cf-unik/unik,emc-advanced-dev/unik,cf-unik/unik,emc-advanced-dev/unik,cf-unik/unik,cf-unik/unik,emc-advanced-dev/unik,emc-advanced-dev/unik,emc-advanced-dev/unik,emc-advanced-dev/unik,emc-advanced-dev/unik