error with copyLogbackXml using sbt-plugin 2.2.0

I am attempting to migrate from gatling sbt-plugin 1.0 to the latest. I tried adding 2.2.3 as above but it was not resolved in the build 

I am using sbt.version 0.13.5) - sbt.ResolveException: unresolved dependency: io.gatling#gatling-sbt;2.2.3: not found

I changed to 2.2.0 and this did get resolved.