Update README.md

Author: johnA1331

Diff for: code-generation/README.md

@@ -7,3 +7,4 @@ This module contains articles about automatic code generation
 - [Introduction to AutoValue](https://www.baeldung.com/introduction-to-autovalue)
 - [Introduction to AutoFactory](https://www.baeldung.com/autofactory)
 - [Google AutoService](https://www.baeldung.com/google-autoservice)
+- [Defensive Copies for Collections Using AutoValue](https://www.baeldung.com/autovalue-defensive-copies)