style(rubocop): fix all safe auto correctable offenses

script/queue_size.rb

@@ -1,7 +1,7 @@
 #!/usr/bin/env ruby
-require_relative '../lib/postal/config'
-require 'mysql2'
+require_relative "../lib/postal/config"
+require "mysql2"
 
-client = Mysql2::Client.new(:host => Postal.config.main_db.host, :username => Postal.config.main_db.username, :password => Postal.config.main_db.password, :port => Postal.config.main_db.port, :database => Postal.config.main_db.database)
+client = Mysql2::Client.new(host: Postal.config.main_db.host, username: Postal.config.main_db.username, password: Postal.config.main_db.password, port: Postal.config.main_db.port, database: Postal.config.main_db.database)
 result = client.query("SELECT COUNT(id) as size FROM `queued_messages` WHERE retry_after IS NULL OR retry_after <= ADDTIME(UTC_TIMESTAMP(), '30') AND locked_at IS NULL")
-puts result.to_a.first['size']
+puts result.to_a.first["size"]