PyYAML fix

Change-Id: Ifa9e802b08b0ad19f9e233f933f398db49f1e769
Signed-off-by: Mark Beierl <mark.beierl@canonical.com>
diff --git a/requirements.in b/requirements.in
index d5c0bcd..8cf88aa 100644
--- a/requirements.in
+++ b/requirements.in
@@ -15,6 +15,6 @@
 deepdiff
 jsonschema>=3.2.0
 python-keystoneclient
-pyyaml==5.3.1
+pyyaml>6
 requests
 tacacs_plus