Update _config.yml

Author: tipsy

_config.yml

@@ -1,7 +1,7 @@
 javalinThreeVersion: 3.13.13
 javalinFourVersion: 4.6.7
 javalinFiveVersion: 5.6.4
-javalinversion: 6.6.0
+javalinversion: 6.7.0
 slf4jversion: 2.0.17
 repourl: https://github.com/javalin/website
 description: Javalin - A lightweight Java and Kotlin web framework. Create REST APIs in Java or Kotlin easily.