Update deprecated use of yaml.load

Update the deprecated use of `yaml.load` without a loader, replacing it with a call to the sugar method `yaml.safe_load`. See also: https://github.com/yaml/pyyaml/wiki/PyYAML-yaml.load(input)-Deprecation

Change-Id: Ia5b591349ba6da4260545335315d3d07191f76cf
Signed-off-by: Adam Israel <adam.israel@canonical.com>
diff --git a/n2vc/k8s_helm_conn.py b/n2vc/k8s_helm_conn.py
index cd15d73..eac34d4 100644
--- a/n2vc/k8s_helm_conn.py
+++ b/n2vc/k8s_helm_conn.py
@@ -894,7 +894,7 @@
             for key in params:
                 value = params.get(key)
                 if '!!yaml' in str(value):
-                    value = yaml.load(value[7:])
+                    value = yaml.safe_load(value[7:])
                 params2[key] = value
 
             values_file = get_random_number() + '.yaml'