Bump rake version to resolve vulnerability notification

telegram-bot.gemspec

@@ -27,5 +27,5 @@ Gem::Specification.new do |spec|
   spec.add_dependency 'httpclient', '~> 2.7'
 
   spec.add_development_dependency 'bundler', '> 1.16'
-  spec.add_development_dependency 'rake', '~> 10.0'
+  spec.add_development_dependency 'rake', '~> 13.0'
 end