Update release notes

Author: plamentotev

README.md

@@ -17,5 +17,6 @@ mvn -Preporting verify site site:stage scm-publish:publish-scm
 You can find details about the different releases in the
 [Release Notes](https://github.com/codehaus-plexus/plexus-io/blob/master/ReleaseNotes.md).
 
+ * [Release 3.1.0](https://github.com/codehaus-plexus/plexus-io/blob/master/ReleaseNotes.md#plexus-io-310).
  * [Release 3.0.1](https://github.com/codehaus-plexus/plexus-io/blob/master/ReleaseNotes.md#plexus-io-301).
  * [Release 3.0.0](https://github.com/codehaus-plexus/plexus-io/blob/master/ReleaseNotes.md#plexus-io-300).

ReleaseNotes.md

@@ -1,6 +1,16 @@
 Plexus-IO Release Notes
 ========================================================================
 
+Plexus IO 3.1.0
+---------------
+
+Plexus IO 3.1.0 requires Java 7.
+
+### New Features
+
+ * [Pull Request #14][pr-14] - Add new FileMapper for giving a suffix to filename:
+   `SuffixFileMapper`
+
 Plexus IO 3.0.1
 ---------------
 
@@ -207,3 +217,4 @@ Plexus IO 2.0.12
 [pr-1]: https://github.com/codehaus-plexus/plexus-io/pull/1
 [pr-3]: https://github.com/codehaus-plexus/plexus-io/pull/3
 [pr-5]: https://github.com/codehaus-plexus/plexus-io/pull/5
+[pr-14]: https://github.com/codehaus-plexus/plexus-io/pull/14