Update README.md

Author: HunorVadaszPerhat

README.md

@@ -8,4 +8,5 @@
 * Inner class:
   * Nested Inner class | [link](https://github.com/HunorVadaszPerhat/java-studies/tree/main/inner_class/nested_inner_class)
   * Local Inner class | [link](https://github.com/HunorVadaszPerhat/java-studies/tree/main/inner_class/local_inner_class)
+  * Anonymous Inner class | [link](https://github.com/HunorVadaszPerhat/java-studies/tree/main/inner_class/anonymous_inner_class)