Bump rubocop from 1.27.0 to 1.28.2 (mastodon#18084)

Bumps [rubocop](https://github.com/rubocop/rubocop) from 1.27.0 to 1.28.2.
- [Release notes](https://github.com/rubocop/rubocop/releases)
- [Changelog](https://github.com/rubocop/rubocop/blob/master/CHANGELOG.md)
- [Commits](rubocop/rubocop@v1.27.0...v1.28.2)

---
updated-dependencies:
- dependency-name: rubocop
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Gemfile

@@ -132,7 +132,7 @@ group :development do
   gem 'letter_opener', '~> 1.8'
   gem 'letter_opener_web', '~> 2.0'
   gem 'memory_profiler'
-  gem 'rubocop', '~> 1.27', require: false
+  gem 'rubocop', '~> 1.28', require: false
   gem 'rubocop-rails', '~> 2.14', require: false
   gem 'brakeman', '~> 5.2', require: false
   gem 'bundler-audit', '~> 0.9', require: false

Gemfile.lock

@@ -442,7 +442,7 @@ GEM
     orm_adapter (0.5.0)
     ox (2.14.11)
     parallel (1.22.1)
-    parser (3.1.1.0)
+    parser (3.1.2.0)
       ast (~> 2.4.1)
     parslet (2.0.0)
     pastel (0.8.0)
@@ -534,7 +534,7 @@ GEM
     redis (4.5.1)
     redis-namespace (1.8.2)
       redis (>= 3.0.4)
-    regexp_parser (2.3.0)
+    regexp_parser (2.3.1)
     request_store (1.5.1)
       rack (>= 1.4)
     responders (3.0.1)
@@ -569,13 +569,13 @@ GEM
     rspec-support (3.11.0)
     rspec_junit_formatter (0.5.1)
       rspec-core (>= 2, < 4, != 2.12.0)
-    rubocop (1.27.0)
+    rubocop (1.28.2)
       parallel (~> 1.10)
       parser (>= 3.1.0.0)
       rainbow (>= 2.2.2, < 4.0)
       regexp_parser (>= 1.8, < 3.0)
       rexml
-      rubocop-ast (>= 1.16.0, < 2.0)
+      rubocop-ast (>= 1.17.0, < 2.0)
       ruby-progressbar (~> 1.7)
       unicode-display_width (>= 1.4.0, < 3.0)
     rubocop-ast (1.17.0)
@@ -825,7 +825,7 @@ DEPENDENCIES
   rspec-rails (~> 5.1)
   rspec-sidekiq (~> 3.1)
   rspec_junit_formatter (~> 0.5)
-  rubocop (~> 1.27)
+  rubocop (~> 1.28)
   rubocop-rails (~> 2.14)
   ruby-progressbar (~> 1.11)
   sanitize (~> 6.0)