Include version in boot message

proxy/src/main/java/com/velocitypowered/proxy/Velocity.java

@@ -19,7 +19,7 @@ public class Velocity {
 
     public static void main(String... args) {
         startTime = System.currentTimeMillis();
-        logger.info("Booting up Velocity...");
+        logger.info("Booting up Velocity {}...", Velocity.class.getPackage().getImplementationVersion());
 
         VelocityServer server = new VelocityServer();
         server.start();