Prepare release PSync 0.5.0

Refs: #5328
Change-Id: Idcde005541499f0fae3df0c4548c634b005410e8
diff --git a/docs/conf.py b/docs/conf.py
index dd5c245..b1b3e65 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -72,7 +72,7 @@
 # -- Misc options ------------------------------------------------------------
 
 doxylink = {
-    'PSync': ('PSync.tag', 'doxygen/'),
+    'psync': ('PSync.tag', 'doxygen/'),
 }
 
 extlinks = {