Compilation error with awaitility_scala in Gatling project

[mdpete...@comcast.net]

I added the following maven dependency to the POM for  a gatling test project:

<dependency>
  <groupId>org.awaitility</groupId>
  <artifactId>awaitility-scala</artifactId>
  <version>3.1.0</version>
</dependency>

But now when I try to run Gatling tests, I get this compilation error:

|Exception in thread "main" java.lang.AbstractMethodError: Method Engine$.scala$App$_setter_$executionStart_$eq(J)V is abstract

at Engine$.scala$App$_setter_$executionStart_$eq(Engine.scala)

at scala.App$class.$init$(App.scala:44)

at Engine$.<init>(Engine.scala:4)

at Engine$.<clinit>(Engine.scala)

at Engine.main(Engine.scala)