chore(deps): bump rubocop-rails from 2.25.1 to 2.26.1

Bumps [rubocop-rails](https://github.com/rubocop/rubocop-rails) from 2.25.1 to 2.26.1.
- [Release notes](https://github.com/rubocop/rubocop-rails/releases)
- [Changelog](https://github.com/rubocop/rubocop-rails/blob/master/CHANGELOG.md)
- [Commits](rubocop/rubocop-rails@v2.25.1...v2.26.1)

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

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

Gemfile.lock

@@ -356,10 +356,10 @@ GEM
     rubocop-performance (1.21.1)
       rubocop (>= 1.48.1, < 2.0)
       rubocop-ast (>= 1.31.1, < 2.0)
-    rubocop-rails (2.25.1)
+    rubocop-rails (2.26.1)
       activesupport (>= 4.2.0)
       rack (>= 1.1)
-      rubocop (>= 1.33.0, < 2.0)
+      rubocop (>= 1.52.0, < 2.0)
       rubocop-ast (>= 1.31.1, < 2.0)
     ruby-progressbar (1.13.0)
     ruby2_keywords (0.0.5)
@@ -394,7 +394,7 @@ GEM
     turbolinks-source (5.2.0)
     tzinfo (2.0.6)
       concurrent-ruby (~> 1.0)
-    unicode-display_width (2.5.0)
+    unicode-display_width (2.6.0)
     version_gem (1.1.4)
     warden (1.2.9)
       rack (>= 2.0.9)