Butane example no longer builds

[fifofonix]

Standard docker build on the butane example yields an error indicating ignition-apply cannot run:

...
 => ERROR [stage-1  3/14] RUN /usr/libexec/ignition-apply mdatp.ign && rm -f mdatp.ign                                                                                                                                                                                                 0.1s
------                                                                                                                                                                                                                                                                                      
 > [stage-1  3/14] RUN /usr/libexec/ignition-apply mdatp.ign && rm -f mdatp.ign:
0.109 INFO     : Ignition 2.18.0
0.111 CRITICAL : failed to apply: this tool is not designed to run on a host system; reprovision the machine instead