Update Akka 2.6.0

Also Scala to 2.13

Trying to undo mess

src/main/g8/default.properties

diff --git a/src/main/g8/default.properties b/src/main/g8/default.properties
index 74e0027..8a9f6dd 100644
--- a/src/main/g8/default.properties
+++ b/src/main/g8/default.properties
@@ -1,5 +1,5 @@
 name = akka-quickstart-java
 description = Akka is a toolkit and runtime for building highly concurrent, distributed, and fault tolerant event-driven apps. This simple application will get you started building Actor based systems with Java.
-scala_version=2.12.8
+scala_version=2.13.1
 # TODO: update to stable once 2.6 has been released
-akka_version=2.6.0-RC1
+akka_version=2.6.0

src/main/g8/src/main/resources/logback.xml

diff --git a/src/main/g8/src/main/resources/logback.xml b/src/main/g8/src/main/resources/logback.xml
index 417ea4e..203596d 100644
--- a/src/main/g8/src/main/resources/logback.xml
+++ b/src/main/g8/src/main/resources/logback.xml
@@ -1,15 +1,21 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <configuration>
-    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
-        <filter class="ch.qos.logback.classic.filter.ThresholdFilter">
-            <level>INFO</level>
-        </filter>
+    <!-- This is a development logging configuration that logs to standard out, for an example of a production
+        logging config, see the Akka docs: https://doc.akka.io/docs/akka/2.6/typed/logging.html#logback -->
+    <appender name="STDOUT" target="System.out" class="ch.qos.logback.core.ConsoleAppender">
         <encoder>
             <pattern>[%date{ISO8601}] [%level] [%logger] [%thread] [%X{akkaSource}] - %msg%n</pattern>
         </encoder>
     </appender>
 
-    <root level="DEBUG">
-        <appender-ref ref="STDOUT"/>
+    <appender name="ASYNC" class="ch.qos.logback.classic.AsyncAppender">
+        <queueSize>1024</queueSize>
+        <neverBlock>true</neverBlock>
+        <appender-ref ref="STDOUT" />
+    </appender>
+
+    <root level="INFO">
+        <appender-ref ref="ASYNC"/>
     </root>
-</configuration>
\ No newline at end of file
+
+</configuration>