Update simplecov to 0.9.0 to fix exit code issues
Simplecov had an issue with exit codes where it would return a success code even if the previous tests failed. See https://github.com/colszowka/simplecov/issues/281
This has been fixed in 0.9.0 with this pull request https://github.com/colszowka/simplecov/pull/303
We are running the gitlab-ce tests on jenkins, which is where we were seeing that ruby exceptions in the spinach tests weren't failing our builds.