Codeship: CI_COMMIT_MESSAGE should be CI_MESSAGE

[camjc]

Master doesn't work with codeship, so this fixes that by renaming the env variable.

See list of built-in ENV variables: https://documentation.codeship.com/basic/builds-and-configuration/set-environment-variables/#default-environment-variables

[camjc]

Ah jeez, I’ve since learned that codeship pro uses the name in master, while codeshup regular uses the one I propose. Do you folks thing we should look at both or what’s the best thing to do?

[camjc]

I've switched over to renovate anyway, closing.