Update to java 17

Author: chbloemer

pom.xml

@@ -2,7 +2,7 @@
     <modelVersion>4.0.0</modelVersion>
     <groupId>de.neuland-bfi</groupId>
     <artifactId>pug4j</artifactId>
-    <version>2.4.1-SNAPSHOT</version>
+    <version>3.0.0-SNAPSHOT</version>
     <packaging>jar</packaging>
     <name>pug4j</name>
     <description>Java implementation of the pug templating language</description>