Fix type in requirements file

Change-Id: I1ab34407c59cc1f3a101f078518613001ca809f6
Related-Prod: PROD-34533
(cherry picked from commit f5df2020475d7ce8066e7b2e9d9684acf8a850a4)
diff --git a/src/com/mirantis/mk/Openstack.groovy b/src/com/mirantis/mk/Openstack.groovy
index 94fc663..98df398 100644
--- a/src/com/mirantis/mk/Openstack.groovy
+++ b/src/com/mirantis/mk/Openstack.groovy
@@ -57,7 +57,7 @@
         // NOTE: pin client packages to current latest to prevent
         // downloading packages which are not support Python 2.7
         'python-openstackclient==4.0.0',
-        'python-heatclient=1.18.0',
+        'python-heatclient==1.18.0',
         'docutils==0.16'
     ]