Update for 1.6.4

By: Erik Broes <erikbroes@grum.nl>

paper-server/pom.xml

@@ -39,7 +39,7 @@
     <dependency>
       <groupId>org.bukkit</groupId>
       <artifactId>minecraft-server</artifactId>
-      <version>1.6</version>
+      <version>1.6.4</version>
       <type>jar</type>
       <scope>compile</scope>
     </dependency>