Update release-notes.xml (#133)

In the 2.0.17 release notes section, I changed "Apache log4net 2.0.16 addresses reported issues" to "Apache log4net 2.0.17 addresses reported issues".
diff --git a/src/site/xdoc/release/release-notes.xml b/src/site/xdoc/release/release-notes.xml
index 1c4948c..48af4ff 100644
--- a/src/site/xdoc/release/release-notes.xml
+++ b/src/site/xdoc/release/release-notes.xml
@@ -28,7 +28,7 @@
 
     <section id="main" name="Apache log4net&#x2122; Release Notes">
       <section id="a2.0.17" name="2.0.17">
-        Apache log4net 2.0.16 addresses reported issues:
+        Apache log4net 2.0.17 addresses reported issues:
         <section id="a2.0.17-bug" name="Bug fixes">
           <ul>
             <li>