scrub_fields config required to be scalar

[ajtran]

the issue is in this line here

https://github.com/rollbar/rollbar-php-symfony3-bundle/blob/d47dcdbf61a54e28a26c8a747037d239b9e3e3ba/DependencyInjection/Configuration.php#L52

in that all config values are marked as scalar.

internal: https://app.intercom.io/a/apps/rlisg82q/inbox/inbox/conversation/17457458725

[ArturMoczulski]

I believe this has been fixed in master and tag v3.0.0.. let me know if you're still experiencing problems and I'll reopen.