Raise min of oslo.db to 11.0.0
Our current min is the victoria release of oslo.db; let's update
to the xena series (which we've been testing with anyway).
@@ -17,7 +17,7 @@ oauth2client>=4.1.3 # Apache-2.0
oslo.config>=8.3.2 # Apache-2.0
oslo.concurrency>=4.4.0 # Apache-2.0
oslo.context>=3.1.1 # Apache-2.0
-oslo.db>=8.4.0 # Apache-2.0
+oslo.db>=11.0.0 # Apache-2.0
oslo.log>=4.5.0 # Apache-2.0
oslo.messaging>=12.5.0 # Apache-2.0
oslo.middleware>=4.1.1 # Apache-2.0
