Constrain ci_reporter dependency to < 2.0

ci_reporter 2.0 was just released and it breaks minitest-chef-handler
as follows:

```
LoadError: cannot load such file -- ci/reporter/minitest
```

Until we're fully compatible with ci_reporter 2, this should resolve
the issue.
Merge pull request #82 from mfischer-zd/master

Constrain ci_reporter dependency to < 2.0