Update README.md

Author: johnA1331

core-scala/README.md

@@ -10,3 +10,4 @@ This module contains articles about Scala's core features
 - [A Guide to Scala Tuples](https://www.baeldung.com/scala/tuples)
 - [Tail Recursion in Scala](https://www.baeldung.com/scala/tail-recursion)
 - [Guide to lazy val in Scala](https://www.baeldung.com/scala/lazy-val)
+- [Partial Functions in Scala](https://www.baeldung.com/scala/partial-functions)