Fix line breaks configuration feature (nl2br)

| Q             | A
| -------------:| ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #83
| License       | MIT

Line breaks Decoda configuration was [added since version 6.2.0](https://github.com/milesj/Decoda/compare/6.1.0...6.2.0). To keep back compatibility it use `Decoda::setConfig()`.