Change haml gem dependency to be pessimistic
Change haml gem dependency to be pessimistic

This is better practice.

Change-Id: Ia9d2a840cec784c0ef3ebf108fb478f4c76376c9
Reviewed-on: http://gerrit.causes.com/40431
Tested-by: jenkins <d95b56ce41a2e1ac4cecdd398defd7414407cc08@causes.com>
Reviewed-by: Shane da Silva <67fb7bfe39f841b16a1f86d3928acc568d12c716@brigade.com>

mzp/haml-lint,skateman/haml-lint