Fix Rubocop warnings about missing "department" for overrides

The cop `Migration/DepartmentName` was tripping over some un-prefixed
overrides, this is a new warning in Rubocop 0.75 that we can fix
trivially.

Author: Nick Campbell

lib/rubocop/cop/rspec/implicit_expect.rb

@@ -82,7 +82,7 @@ def offending_expect(node)
           end
         end
 
-        def is_expected_range(source_map) # rubocop:disable PredicateName
+        def is_expected_range(source_map) # rubocop:disable Naming/PredicateName
           Parser::Source::Range.new(
             source_map.expression.source_buffer,
             source_map.expression.begin_pos,

spec/project/changelog_spec.rb

@@ -39,7 +39,7 @@
       it 'has a valid URL' do
         issues.each do |issue|
           number = issue[:number].gsub(/\D/, '')
-          pattern = %r{^https://github\.com/.+/.+/(?:issues|pull)/#{number}$} # rubocop:disable LineLength
+          pattern = %r{^https://github\.com/.+/.+/(?:issues|pull)/#{number}$} # rubocop:disable Metrics/LineLength
           expect(issue[:url]).to match(pattern)
         end
       end

spec/rubocop/cop/rspec/cop_spec.rb

@@ -21,13 +21,15 @@
 
   let(:fake_cop) do
     stub_const('RuboCop::RSpec', Module.new)
-    # rubocop:disable ClassAndModuleChildren, RSpec/LeakyConstantDeclaration
+    # rubocop:disable Style/ClassAndModuleChildren
+    # rubocop:disable RSpec/LeakyConstantDeclaration
     class RuboCop::RSpec::FakeCop < described_class
       def on_send(node)
         add_offense(node, message: 'I flag everything')
       end
     end
-    # rubocop:enable ClassAndModuleChildren, RSpec/LeakyConstantDeclaration
+    # rubocop:enable Style/ClassAndModuleChildren
+    # rubocop:enable RSpec/LeakyConstantDeclaration
     RuboCop::RSpec::FakeCop
   end