Allow newer awesome_print versions

The current gemspec specifies an old version of awesome_print, which conflicts with `metric_fu`:

    Bundler could not find compatible versions for gem "awesome_print":
      In Gemfile:
        pact (>= 0) ruby depends on
          awesome_print (~> 1.1.0) ruby

        metric_fu (>= 0) ruby depends on
          awesome_print (1.2.0)

Considering `awesome_print` is a fairly inconspicuous gem I've taken the liberty of allowing minor version updates (`~> 1.1`) instead of restricting us to patch updates on old releases.