Update README.md

Author: amnabibi786

core-kotlin-modules/core-kotlin-advanced-3/README.md

@@ -4,4 +4,5 @@
 - [Passing a Type to Generic Method in Kotlin](https://www.baeldung.com/kotlin/generic-methods)
 - [Getting a Kotlin KClass from a Package Class Name String](https://www.baeldung.com/kotlin/kclass-fqn-string)
 - [A Guide to Kotlin Context Receivers](https://www.baeldung.com/kotlin/context-receivers)
+- [Serialize/Deserialize Kotlin Sealed Class](https://www.baeldung.com/kotlin/sealed-class-serialization)
 - More articles: [[<-- prev]](../core-kotlin-advanced-2)