Enable fairness on Kinesis Source's SynchronousQueue

This fixes a possible problem in which some Kinesis shards progress more
quickly than others. Each KCL shard processor has its own thread, and
each calls `queue.put()` on the synchronous queue.  It is possible that
by luck some shard/threads were having their `put()` accepted by a
consumer more quickly.

modules/kinesis/src/main/scala/com/snowplowanalytics/snowplow/sources/kinesis/KinesisSource.scala

@@ -46,7 +46,7 @@ object KinesisSource {
     config: KinesisSourceConfig,
     liveness: Ref[F, FiniteDuration]
   ): Stream[F, Stream[F, LowLevelEvents[Map[String, Checkpointable]]]] = {
-    val actionQueue = new SynchronousQueue[KCLAction]()
+    val actionQueue = new SynchronousQueue[KCLAction](true)
     for {
       _ <- Stream.resource(KCLScheduler.populateQueue[F](config, actionQueue))
       events <- Stream.emit(pullFromQueueAndEmit(actionQueue, liveness).stream).repeat