[RELEASE] Released version 2.6-dev0

Released version 2.6-dev0 with the following main changes :
    - MINOR: version: it's development again
diff --git a/doc/configuration.txt b/doc/configuration.txt
index 62bf226..737a0d3 100644
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -2,7 +2,7 @@
                                 HAProxy
                           Configuration Manual
                          ----------------------
-                              version 2.5
+                              version 2.6
                              willy tarreau
                               2021/11/23
 
diff --git a/doc/intro.txt b/doc/intro.txt
index 517ca2c..8c06004 100644
--- a/doc/intro.txt
+++ b/doc/intro.txt
@@ -1,7 +1,7 @@
                              -----------------------
                               HAProxy Starter Guide
                              -----------------------
-                                   version 2.5
+                                   version 2.6
 
 
 This document is an introduction to HAProxy for all those who don't know it, as
diff --git a/doc/management.txt b/doc/management.txt
index 146ae2e..763f5f2 100644
--- a/doc/management.txt
+++ b/doc/management.txt
@@ -1,7 +1,7 @@
                              ------------------------
                              HAProxy Management Guide
                              ------------------------
-                                   version 2.5
+                                   version 2.6
 
 
 This document describes how to start, stop, manage, and troubleshoot HAProxy,