style(rubocop): fix all safe auto correctable offenses

app/models/ip_pool.rb

@@ -18,16 +18,16 @@ class IPPool < ApplicationRecord
 
   include HasUUID
 
-  validates :name, :presence => true
+  validates :name, presence: true
 
-  has_many :ip_addresses, :dependent => :restrict_with_exception
-  has_many :servers, :dependent => :restrict_with_exception
-  has_many :organization_ip_pools, :dependent => :destroy
-  has_many :organizations, :through => :organization_ip_pools
-  has_many :ip_pool_rules, :dependent => :destroy
+  has_many :ip_addresses, dependent: :restrict_with_exception
+  has_many :servers, dependent: :restrict_with_exception
+  has_many :organization_ip_pools, dependent: :destroy
+  has_many :organizations, through: :organization_ip_pools
+  has_many :ip_pool_rules, dependent: :destroy
 
   def self.default
-    where(:default => true).order(:id).first
+    where(default: true).order(:id).first
   end
 
 end