Set TargetRubyVersion of RuboCop to 2.5 (#31128).

git-svn-id: http://svn.redmine.org/redmine/trunk@20904 e93f8b46-1217-0410-a6f0-8f06a7374b81

.rubocop.yml

 inherit_from: .rubocop_todo.yml
 
 AllCops:
-  TargetRubyVersion: 2.4
+  TargetRubyVersion: 2.5
   TargetRailsVersion: 5.2
 
   NewCops: enable

.rubocop_todo.yml

     - 'test/integration/api_test/issues_test.rb'
     - 'test/integration/attachments_test.rb'
 
+# Cop supports --auto-correct.
+Performance/RedundantEqualityComparisonBlock:
+  Exclude:
+    - 'app/models/query.rb'
+    - 'app/models/setting.rb'
+    - 'lib/redmine/field_format.rb'
+    - 'test/integration/api_test/issues_test.rb'
+
 # Cop supports --auto-correct.
 Performance/RedundantMatch:
   Exclude:
 # Cop supports --auto-correct.
 Style/RedundantBegin:
   Exclude:
+    - 'app/controllers/issues_controller.rb'
+    - 'app/models/auth_source.rb'
     - 'app/models/member.rb'
+    - 'app/models/repository.rb'
+    - 'app/models/setting.rb'
+    - 'lib/redmine/codeset_util.rb'
+    - 'lib/redmine/plugin.rb'
+    - 'test/unit/issue_nested_set_concurrency_test.rb'
+    - 'test/unit/project_nested_set_concurrency_test.rb'
+    - 'test/unit/query_test.rb'
 
 # Cop supports --auto-correct.
 Style/RedundantCondition: