Update rubocop, add appraisal gem

lib/telegram/bot/updates_controller/instrumentation.rb

@@ -39,7 +39,7 @@ module Telegram
           Instrumentation.instrument(:respond_with, type: type) { super }
         end
 
-        %i(answer_callback_query answer_inline_query).each do |type|
+        %i[answer_callback_query answer_inline_query].each do |type|
           define_method(type) do |*args|
             Instrumentation.instrument(:respond_with, type: type) { super(*args) }
           end

lib/telegram/bot/updates_controller/log_subscriber.rb

@@ -17,7 +17,7 @@ module Telegram
             payload   = event.payload
             additions = UpdatesController.log_process_action(payload)
             message = "Completed in #{event.duration.round}ms"
-            message << " (#{additions.join(' | ')})" unless additions.blank?
+            message << " (#{additions.join(' | ')})" if additions.present?
             message
           end
         end

lib/telegram/bot/updates_controller/testing.rb

@@ -2,7 +2,7 @@ module Telegram
   module Bot
     class UpdatesController
       module Testing
-        IVARS_TO_KEEP = %i(@_session).freeze
+        IVARS_TO_KEEP = %i[@_session].freeze
 
         # Perform multiple dispatches on same instance.
         def dispatch_again(bot = nil, update = nil)