Add new rubocop rules and fix the single offence

.rubocop_styleguide.yml

@@ -40,6 +40,12 @@ Layout/MultilineMethodCallIndentation:
 Layout/LineLength:
   Max: 100
 
+Lint/RaiseException:
+  Enabled: true
+
+Lint/StructNewOverride:
+  Enabled: true
+
 ## TEMPORARY/CONTESTED SETTINGS
 #
 # These are still to be decided upon, but recommended for inclusion by

spec/models/spree/tax_rate_spec.rb

@@ -61,7 +61,7 @@ module Spree
 
       it "restores both values when an exception is raised" do
         expect do
-          tax_rate.send(:with_tax_included_in_price) { raise Exception, 'oops' }
+          tax_rate.send(:with_tax_included_in_price) { raise StandardError, 'oops' }
         end.to raise_error 'oops'
 
         expect(tax_rate.included_in_price).to be false