Upgrade annotate from 2.6.10 to 2.7.0

Includes compatibility with Rails 5. We don’t have any tests for this,
so no need to run them. [ci skip]

Changelog: https://github.com/ctran/annotate_models/releases/tag/v2.7.0

Working towards #14286.

Gemfile

@@ -239,7 +239,7 @@ group :development do
   gem "foreman"
   gem 'brakeman', '~> 3.2.0', require: false
 
-  gem "annotate", "~> 2.6.0"
+  gem "annotate", "~> 2.7.0"
   gem "letter_opener", '~> 1.1.2'
   gem 'quiet_assets', '~> 1.0.2'
   gem 'rerun', '~> 0.11.0'

Gemfile.lock

@@ -51,8 +51,8 @@ GEM
       activerecord (>= 3.0)
     akismet (2.0.0)
     allocations (1.0.4)
-    annotate (2.6.10)
-      activerecord (>= 3.2, <= 4.3)
+    annotate (2.7.0)
+      activerecord (>= 3.2, < 6.0)
       rake (~> 10.4)
     arel (6.0.3)
     asana (0.4.0)
@@ -888,7 +888,7 @@ DEPENDENCIES
   after_commit_queue
   akismet (~> 2.0)
   allocations (~> 1.0)
-  annotate (~> 2.6.0)
+  annotate (~> 2.7.0)
   asana (~> 0.4.0)
   asciidoctor (~> 1.5.2)
   attr_encrypted (~> 1.3.4)