[RELEASE] Released version 2.3-dev0

Released version 2.3-dev0 with the following main changes :
    - exact copy of 2.2.0
diff --git a/CHANGELOG b/CHANGELOG
index 4274ffe..656586d 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,6 +1,9 @@
 ChangeLog :
 ===========
 
+2020/07/07 : 2.3-dev0
+    - exact copy of 2.2.0
+
 2020/07/07 : 2.2.0
     - BUILD: mux-h2: fix typo breaking build when using DEBUG_LOCK
     - CLEANUP: makefile: update the outdated list of DEBUG_xxx options