Update the release date

Author: zsxwing

CHANGES.md

@@ -1,6 +1,6 @@
 # RxScala Releases
 
-## Version 0.26.3 - TODO ([Maven Central](http://search.maven.org/#search%7Cga%7C1%7C%22rxscala%22%20AND%20g%3A%22io.reactivex%22))
+## Version 0.26.3 - Oct 8th 2016 ([Maven Central](http://search.maven.org/#search%7Cga%7C1%7C%22rxscala%22%20AND%20g%3A%22io.reactivex%22))
 
 This release upgrades RxJava to 1.2.0, adds new RxScala/RxJava converters (See
 [JavaConvertersDemo.scala](https://github.com/ReactiveX/RxScala/blob/0.x/examples/src/test/scala/examples/JavaConvertersDemo.scala)