example plugin: update the config and README

Author: Trevor159

README.md

@@ -0,0 +1,2 @@
+# Example
+An example greeter plugin

src/main/java/com/example/ExampleConfig.java

@@ -1,4 +1,3 @@
-
 package com.example;
 
 import net.runelite.client.config.Config;