Update client.rb (#180)

See #179. This should be `data_bags` per https://github.com/chef/chef/blob/61a11902ab814aad3625eb4da7e3345d63ee7c09/knife/lib/chef/knife/data_bag_from_file.rb#L64

lib/taste_tester/client.rb

@@ -199,7 +199,7 @@ def bundle_upload
             )
             populate(
               stream, writer, TasteTester::Config.relative_databag_dir,
-              'databag'
+              'data_bags'
             )
           end
           stream.close