Update pip requirements

Change-Id: Ie13a8e81a0182b9b9b6f37c17ae454793f658c47
Signed-off-by: garciadeblas <gerardo.garciadeblas@telefonica.com>
diff --git a/tox.ini b/tox.ini
index ca1afaf..60fab11 100644
--- a/tox.ini
+++ b/tox.ini
@@ -202,7 +202,7 @@
 
 #######################################################################################
 [testenv:pip-compile]
-deps =  pip-tools==6.4.0
+deps =  pip-tools==6.6.2
 skip_install = true
 whitelist_externals = bash
         [