Relax bundler version constraints

Author: Forest Carlisle

tracker_api.gemspec

@@ -18,7 +18,7 @@ Gem::Specification.new do |spec|
   spec.test_files    = spec.files.grep(%r{^(test|spec|features)/})
   spec.require_paths = ['lib']
 
-  spec.add_development_dependency 'bundler', '> 1.3', '< 2.1'
+  spec.add_development_dependency 'bundler', '> 1.3'
   spec.add_development_dependency 'rake'
   spec.add_development_dependency 'minitest'
   spec.add_development_dependency 'mocha'