update example to most recent released version

Author: Brian McCallister

README.md

@@ -43,7 +43,7 @@ To use it, add a plugin to your pom like
 <plugin>
   <groupId>org.skife.maven</groupId>
   <artifactId>really-executable-jar-maven-plugin</artifactId>
-  <version>1.1.0</version>
+  <version>1.4.1</version>
   <configuration>
     <!-- value of flags will be interpolated into the java invocation -->
     <!-- as "java $flags -jar ..." -->