Bump openstackdocstheme to 1.30.0

...to pick up many improvements, including the return of table borders.

Change-Id: I6af7c339e139f0980c64927fdd7cf3304b0715c5

Author: pengyuesheng

doc/requirements.txt

@@ -2,7 +2,7 @@
 # of appearance. Changing the order has an impact on the overall integration
 # process, which may cause wedges in the gate later.
 
-openstackdocstheme>=1.18.1 # Apache-2.0
+openstackdocstheme>=1.30.0 # Apache-2.0
 sphinx>=1.6.2,!=1.6.6,!=1.6.7,<2.0.0;python_version=='2.7'  # BSD
 sphinx>=1.6.2,!=1.6.6,!=1.6.7,!=2.1.0;python_version>='3.4' # BSD
 reno>=2.5.0 # Apache-2.0

lower-constraints.txt

@@ -19,6 +19,6 @@ mock==2.0 # BSD
 python-openstackclient==3.14 # Apache-2.0
 
 # doc/requirements.txt
-openstackdocstheme==1.18.1 # Apache-2.0
+openstackdocstheme==1.30.0 # Apache-2.0
 sphinx==1.6.2 # BSD
 reno==2.5.0  # Apache2