Revert "remove deprecated env method, bump version to 1.3.0"

[stefannibrasil]

Reverts thoughtbot/climate_control#65

We shouldn't change versions outside the release commit — this makes it easier to see when the release was cut, especially as it'll include CHANGELOG entries too.

I'd also generally wait until releasing a major version. We don't know who's relying on a deprecated method, and seeing a major version coming in and then you're tests failing all of a sudden is a better hint.