updates sass version

Kept running into 
```
Bundler could not find compatible versions for gem "sass":
  In Gemfile:
    alchemy_cms (>= 0) ruby depends on
      sass (>= 3.2.19) ruby

    alchemy_cms (>= 0) ruby depends on
      sass-rails (>= 4.0.4) ruby depends on
        sass (3.2.2)
```
This was the only solution, let me know if you are hitting the same issue