Oracle doc fix (add "key:" to secret) (#750)
Oracle doc fix (add "key:" to secret) (#750)

* fix domain filter match logic to not match similar domain names

* MAINTAINER is deprecated - using LABEL instead

https://docs.docker.com/engine/reference/builder/#maintainer-deprecated

* Fix to documentation for Oracle to include `key:`

kubernetes-incubator/external-dns,kubernetes-incubator/external-dns