Update README.md

Author: lor6

core-java-8/README.md

@@ -30,3 +30,5 @@
 - [The Difference Between map() and flatMap()](http://www.baeldung.com/java-difference-map-and-flatmap)
 - [Merging Streams in Java](http://www.baeldung.com/java-merge-streams)
 - [“Stream has already been operated upon or closed” Exception in Java](http://www.baeldung.com/java-stream-operated-upon-or-closed-exception)
+- [Display All Time Zones With GMT And UTC in Java](http://www.baeldung.com/java-time-zones)
+