Update rubocop

Rakefile

@@ -16,6 +16,6 @@ RSpec::Core::RakeTask.new do |t|
 end
 
 desc 'Lint code'
-Rubocop::RakeTask.new
+RuboCop::RakeTask.new
 
 Bundler::GemHelper.install_tasks

lib/prometheus/client/rack/collector.rb

@@ -33,20 +33,20 @@ def call(env) # :nodoc:
         def init_request_metrics
           @requests = @registry.counter(
             :http_requests_total,
-            'A counter of the total number of HTTP requests made.',)
+            'A counter of the total number of HTTP requests made.')
           @requests_duration = @registry.counter(
             :http_request_durations_total_microseconds,
             'The total amount of time spent answering HTTP requests ' \
             '(microseconds).',)
           @durations = @registry.summary(
             :http_request_durations_microseconds,
-            'A histogram of the response latency (microseconds).',)
+            'A histogram of the response latency (microseconds).')
         end
 
         def init_exception_metrics
           @exceptions = @registry.counter(
             :http_exceptions_total,
-            'A counter of the total number of exceptions raised.',)
+            'A counter of the total number of exceptions raised.')
         end
 
         def trace(env)