Updated from global requirements

OpenStack Proposal Bot · OpenStack Proposal Bot · commit 52dbdd3f1123 · 2018-02-13T02:00:19.000Z
Change-Id: I7415778364af3898e0efe9b3ffcf45ff854657c8
diff --git a/doc/requirements.txt b/doc/requirements.txt
@@ -2,5 +2,5 @@
 # of appearance. Changing the order has an impact on the overall integration
 # process, which may cause wedges in the gate later.
 sphinx!=1.6.6,>=1.6.2 # BSD
-openstackdocstheme>=1.17.0 # Apache-2.0
+openstackdocstheme>=1.18.1 # Apache-2.0
 reno>=2.5.0 # Apache-2.0
