Release Tsunami to version 0.0.23, see release notes

Author: tooryx

build.gradle

@@ -15,7 +15,7 @@ subprojects {
     apply plugin: 'com.github.johnrengelman.shadow'
 
     group = 'com.google.tsunami'
-    version = '0.0.23-SNAPSHOT' // Current Tsunami version
+    version = '0.0.23' // Current Tsunami version
 
     repositories {
         maven { // The google mirror is less flaky than mavenCentral()