Update pip dependencies

Change-Id: Ie6d79cca74ca3e63cede058d516d4bbd6e4a71e6
Signed-off-by: garciadeblas <gerardo.garciadeblas@telefonica.com>
diff --git a/requirements.in b/requirements.in
index 1dd93f6..928eef8 100644
--- a/requirements.in
+++ b/requirements.in
@@ -26,6 +26,7 @@
 gnocchiclient
 humanfriendly
 lxml
+kafka
 prometheus-api-client
 prometheus-client
 python-ceilometerclient