Change gem's .gemspec to accept higher version of ruby-pathspec
Version 7.4.0 bumped the upper limit for pathspec to 3.0.0, permitting the 2.x branch.
With the 7.0.5 version currently in the debian package, the test suite passes all tests without errors with version 2.1.0 of ruby-pathspec so we can bump the gem requirement with a patch until we start shipping 7.4.0+ of puppetlabs_spec_helper