Merge pull request #518 from FriendsOfSymfony/varnish6-doc

show varnish 6 correctly in doc

Author: dbu

doc/conf.py

@@ -269,5 +269,5 @@
 
 config_block = {
     'varnish3': 'Varnish 3',
-    'varnish4': 'Varnish 4 & 5'
+    'varnish4': 'Varnish 4 - 6'
 }