Ensure simplecov version is supported by CodeClimate
Ensure simplecov version is supported by CodeClimate

On Ruby 2.4 simplecov 0.18 is installed which [isn't supported by
CodeClimate][1]. This [was also broken on master][2].

[1]: https://docs.codeclimate.com/docs/configuring-test-coverage
[2]: https://travis-ci.org/github/prontolabs/pronto/jobs/748290009#L1025

Co-authored-by: Ashish Kulkarni <428b6da53085b8fd7b37e9fb259c0c609bd09984@kulkarni.dev>

prontolabs/pronto,mmozuras/pronto