Add links to releases 4.2.2 and 4.2.3

Author: rfscholte

README.md

@@ -18,6 +18,8 @@ This patch has been integrated into the Release 3.6.0
 
 You can find details about the different releases in the [Release Notes](https://github.com/codehaus-plexus/plexus-archiver/blob/master/ReleaseNotes.md).
 
+ * [Release 4.2.3](https://github.com/codehaus-plexus/plexus-archiver/releases/tag/plexus-archiver-4.2.3).
+ * [Release 4.2.2](https://github.com/codehaus-plexus/plexus-archiver/releases/tag/plexus-archiver-4.2.2).
  * [Release 4.2.1](https://github.com/codehaus-plexus/plexus-archiver/blob/master/ReleaseNotes.md#plexus-archiver-421).
  * [Release 4.2.0](https://github.com/codehaus-plexus/plexus-archiver/blob/master/ReleaseNotes.md#plexus-archiver-420).
  * [Release 4.1.0](https://github.com/codehaus-plexus/plexus-archiver/blob/master/ReleaseNotes.md#plexus-archiver-410).