Fix deploy_plugins to exit with non-zero return code on error

[arm4b]

Command that's expected to fail:

docker run \                                                                       
-v $(pwd):/opt/bitops_deployment \
bitovi/bitops:dev

outputs error message as expected:

2022-08-10 12:08:08,065 root         ERROR The `BITOPS_ENVIRONMENT` variable must be set... Exiting.
		For more information on this issue please checkout our doc [https://bitovi.github.io/bitops/configuration-base/#environment]

But it's missing the proper non-zero exit code to signalize a failure in the terminal:

echo $?                                                                               ✔
0

This PR fixes it.