DOC: mention previous version (5.10.1)

RELEASE_NOTES.txt

-OTB-v.6.0.0 - Changes since version 5.10.0 (May 2th, 2017)
+OTB-v.6.0.0 - Changes since version 5.11.0 (May 2th, 2017)
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 * Request for Changes (http://wiki.orfeo-toolbox.org/index.php/Requests_for_Changes):
@@ -35,6 +35,21 @@ OTB-v.6.0.0 - Changes since version 5.10.0 (May 2th, 2017)
   * OTB-applications
     * 0001369: otbgui_Segmentation.bat won't produce correct results
 
+OTB-v.5.10.1 - Changes since version 5.10.0 (March 8th, 2017)
+---------------------------------------------------------------
+
+* Packaging :
+  * Upgrade to GDAL 2.1.3, compatible with new format of Sentinel 2 products
+  * Upgrade of SertitObject external module with bugfixes
+
+* Bugfixes :
+
+  * Orfeo Toolbox (OTB)
+    * 0001364: Crash of Mapla.app v5.10.0 on MacOSX El Captain 10.11.5
+    * 0001365: Python wrapper OTB-5.8.0: @rpath problem on MacOSX El Captain 10.11
+    * 0001367: Monteverdi from the OTB standalone package for Mac OS X fails to run
+    * 0001366: OTB 5.10 : can't use extract ROI using bindings python
+
 OTB-v.5.10.0 - Changes since version 5.8.0 (February 14th, 2017)
 ---------------------------------------------------------------