version update [ci skip]

README.md

@@ -53,7 +53,7 @@ Add the XChart library as a dependency to your pom.xml file:
     <dependency>
         <groupId>com.xeiam.xchart</groupId>
         <artifactId>xchart</artifactId>
-        <version>2.1.0</version>
+        <version>2.2.0</version>
     </dependency>
 
 For snapshots, add the following to your pom.xml file:
@@ -67,7 +67,7 @@ For snapshots, add the following to your pom.xml file:
     <dependency>
       <groupId>com.xeiam</groupId>
       <artifactId>xchart</artifactId>
-      <version>2.2.0-SNAPSHOT</version>
+      <version>2.2.1-SNAPSHOT</version>
     </dependency>
 
 ## Building
@@ -76,7 +76,7 @@ mvn javadoc:aggregate
 
 ## Running Demo
     cd /path/to/xchart-demo/jar/
-    java -cp xchart-demo-2.1.0.jar:xchart-2.1.0.jar com.xeiam.xchart.demo.XChartDemo
+    java -cp xchart-demo-2.2.0.jar:xchart-2.2.0.jar com.xeiam.xchart.demo.XChartDemo
 
 ## Bugs
 Please report any bugs or submit feature requests to [XChart's Github issue tracker](https://github.com/timmolter/XChart/issues).