Relax bundler dependency

telegram-bot.gemspec

@@ -26,6 +26,6 @@ Gem::Specification.new do |spec|
   spec.add_dependency 'activesupport', '>= 4.0', '< 6.0'
   spec.add_dependency 'httpclient', '~> 2.7'
 
-  spec.add_development_dependency 'bundler', '~> 1.16'
+  spec.add_development_dependency 'bundler', '> 1.16'
   spec.add_development_dependency 'rake', '~> 10.0'
 end