title: Gatling scala extension fails with, could not find implicit value for evidence parameter
body: <p>Trying to run a gatling 3.0.2 with a neat exetension method that I have been using many times before with gatling 2.2.x</p>
  
  <pre><code>implicit class Extensions(val scenario: ScenarioBuilder) extends AnyVal {
  def injectDefaults: PopulationBuilder =
    scenario.inject(
      rampUsersPerSec(RAMP_USER_PER_SEC) to LOAD_FACTOR during (RAMP_UP_TIME seconds),
      constantUsersPerSec(LOAD_FACTOR) during (DURATION seconds)
    )
  </code></pre>
  
  <p>}</p>
  
  <p>But it no longer compiles, it fails with:</p>
  
  <pre><code> could not find implicit value for evidence parameter of type 
   io.gatling.core.controller.inject.InjectionProfileFactory[Product with Serializable with io.gatling.core.controller.inject.open.OpenInjectionStep]
    scenario.inject(
  </code></pre>
  
  <p>Anyone knows why?</p>