Bump up version for magnum stein to 8.1.0

Change-Id: I66eacbf2f51b93b94f2aea91d8db5e7f12000c40

Author: brtkwr

kolla/common/config.py

@@ -519,7 +519,7 @@
     'magnum-base': {
         'type': 'url',
         'location': ('$tarballs_base/magnum/'
-                     'magnum-8.0.0.tar.gz')},
+                     'magnum-8.1.0.tar.gz')},
     'manila-base': {
         'type': 'url',
         'location': ('$tarballs_base/manila/'