Deal with failure exit deprecation

[kspurgin]

❯  thor batch add exhlip --csv nhr_exhibition_loanin.csv --rectype nonhierarchicalrelationship --action create
No value provided for required options '--id'
Deprecation warning: Thor exit with status 0 on errors. To keep this behavior, you must define `exit_on_failure?` in `Batch`
You can silence deprecations warning by setting the environment variable THOR_SILENCE_DEPRECATION.