Update README to version 0.2.1

Author: github-actions[bot]

README.md

@@ -25,7 +25,7 @@ Release artifact
 <dependency>
     <groupId>com.github.zrdj</groupId>
     <artifactId>java-identifiers</artifactId>
-    <version>0.2.0</version>
+    <version>0.2.1</version>
 </dependency>
 ```