BAEL-3459 update README (eugenp#8791)

* BAEL-3336 BAEL-3058 add links

* BAEL-3319: add link

* BAEL-3284: add link

* BAEL-3198: add link to article

* BAEL-3479: add link to article

* BAEL-3485: add article link

* SCALA-38: move to new package and add link back to article

* SCALA-38: add imports back into unit test

* BAEL-3459: add link back to article

libraries-3/README.md

@@ -11,3 +11,4 @@ Remember, for advanced libraries like [Jackson](/jackson) and [JUnit](/testing-m
 - [Parsing Command-Line Parameters with JCommander](https://www.baeldung.com/jcommander-parsing-command-line-parameters)
 - [Guide to the Cactoos Library](https://www.baeldung.com/java-cactoos)
 - [Parsing Command-Line Parameters with Airline](https://www.baeldung.com/java-airline)
+- [Introduction to cache2k](https://www.baeldung.com/java-cache2k)