Lock rubyzip to 0-9-x-stable

rubyzip has introduced breaking changes on 1.0.0 as per https://github.com/rubyzip/rubyzip/commit/61ce5dbc5f12d2e7d368d480386347b8920897be

Since neography.gemspec uses >= for dependency versions, new installation of dependencies bring rubyzip 1.0.0 and therefore neography breaks.

Here's the output *before* this fix:

    $ bundle
    $ bundle exec rake

    rake aborted!
    cannot load such file -- zip/zip
    /Users/wagner/Projects/os/neography/lib/neography/tasks.rb:4:in `require'
    /Users/wagner/Projects/os/neography/lib/neography/tasks.rb:4:in `<top (required)>'
    /Users/wagner/Projects/os/neography/Rakefile:5:in `require'
    /Users/wagner/Projects/os/neography/Rakefile:5:in `<top (required)>'

And here's the output *after* this fix:

    $ bundle exec rake

    (hiding verbose output...)

    Finished in 12.83 seconds
    624 examples, 0 failures
    [Coveralls] Outside the Travis environment, not sending data.

Since I could only proof the issue with rubyzip, I only changed rubyzip in neography.gemspec. However that'd be nice to make the same change (replacing >= with ~>) for all the other dependencies as well.