Generate stoplight doc on version with multiple digits

Right now the persist_version job is not triggered since the
regex only take into account versions with one digit after the
decimal point. The regex actually matches but CircleCi needs it
to match the entire string, from their doc:

> Both only and ignore lists can have full names and regular expressions.
> Regular expressions must match the entire string.

https://circleci.com/docs/2.0/configuration-reference/#branches

.circleci/config.yml

@@ -137,7 +137,7 @@ workflows:
       - persist_version:
           filters:
             branches:
-              only: /master|v\d\.\d/
+              only: /master|v\d\.\d+/
       - postgres
       - mysql
       - postgres_rails52