[Scala] Fix missing json4s import (#7271)

* [Scala] Fix missing json4s import

Closes #7270

* Update petstore sample

Author: gmarz

modules/swagger-codegen/src/main/resources/scala/api.mustache

@@ -31,6 +31,8 @@ import scala.concurrent._
 import scala.concurrent.duration._
 import scala.util.{Failure, Success, Try}
 
+import org.json4s._
+
 {{#operations}}
 class {{classname}}(
   val defBasePath: String = "{{{basePath}}}",

samples/client/petstore-security-test/scala/.swagger-codegen/VERSION

@@ -1 +1 @@
-2.3.0-SNAPSHOT
+2.3.0

samples/client/petstore-security-test/scala/build.sbt

@@ -1,22 +1,20 @@
-version       := "1.0.0"
-
-name          := "swagger-scala-client"
-
-organization  := "io.swagger"
-
-scalaVersion  := "2.11.8"
+version := "1.0.0"
+name := "swagger-scala-client"
+organization := "io.swagger"
+scalaVersion := "2.11.12"
 
 libraryDependencies ++= Seq(
-  "com.fasterxml.jackson.module" %% "jackson-module-scala" % "2.4.2",
-  "com.sun.jersey" % "jersey-core" % "1.19",
-  "com.sun.jersey" % "jersey-client" % "1.19",
-  "com.sun.jersey.contribs" % "jersey-multipart" % "1.19",
+  "com.fasterxml.jackson.module" %% "jackson-module-scala" % "2.9.2",
+  "com.fasterxml.jackson.datatype" % "jackson-datatype-joda" % "2.9.2",
+  "com.sun.jersey" % "jersey-core" % "1.19.4",
+  "com.sun.jersey" % "jersey-client" % "1.19.4",
+  "com.sun.jersey.contribs" % "jersey-multipart" % "1.19.4",
   "org.jfarcand" % "jersey-ahc-client" % "1.0.5",
   "io.swagger" % "swagger-core" % "1.5.8",
-  "joda-time" % "joda-time" % "2.2",
-  "org.joda" % "joda-convert" % "1.2",
-  "org.scalatest" %% "scalatest" % "2.2.4" % "test",
-  "junit" % "junit" % "4.8.1" % "test",
+  "joda-time" % "joda-time" % "2.9.9",
+  "org.joda" % "joda-convert" % "1.9.2",
+  "org.scalatest" %% "scalatest" % "3.0.4" % "test",
+  "junit" % "junit" % "4.12" % "test",
   "com.wordnik.swagger" %% "swagger-async-httpclient" % "0.3.5"
 )