Updated from global requirements

Change-Id: I99840204b12ec86a3abafcd64c9fd8ef98e7d7fe
diff --git a/requirements.txt b/requirements.txt
index 14c42b3..26e1f02 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -2,7 +2,7 @@
 # of appearance. Changing the order has an impact on the overall integration
 # process, which may cause wedges in the gate later.
 pbr!=2.1.0,>=2.0.0 # Apache-2.0
-cliff>=2.3.0 # Apache-2.0
+cliff>=2.6.0 # Apache-2.0
 jsonschema!=2.5.0,<3.0.0,>=2.0.0 # MIT
 testtools>=1.4.0 # MIT
 paramiko>=2.0 # LGPLv2.1+