Not able to work with Scala 2.11 when i add this plugin

[sanjaypsachdev]

I am not able to use Scala 2.11 in my test project when i am using this plugin. Below is my build.sbt :

name := "ch19-spark-2"
version := "1.0"
scalaVersion := "2.11.8"
crossScalaVersions := Seq("2.11.8", "2.10.6")
sbtPlugin := true
val sparkVersion = "2.2.0"
libraryDependencies ++= Seq(
"org.apache.spark" %% "spark-core" % sparkVersion
)

my plugin.sbt looks like :

addSbtPlugin("com.julianpeeters" % "sbt-avrohugger" % "0.16.0")

The error that i keep getting is :
Conflicting cross-version suffixes in: org.json4s:json4s-ast, org.json4s:json4s-core