Bump rubocop-rails from 2.17.4 to 2.20.2

Bumps [rubocop-rails](https://github.com/rubocop/rubocop-rails) from 2.17.4 to 2.20.2.
- [Release notes](https://github.com/rubocop/rubocop-rails/releases)
- [Changelog](https://github.com/rubocop/rubocop-rails/blob/master/CHANGELOG.md)
- [Commits](rubocop/rubocop-rails@v2.17.4...v2.20.2)

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

Signed-off-by: dependabot[bot] <[email protected]>

Gemfile.lock

@@ -352,8 +352,9 @@ GEM
     options (2.3.2)
     orm_adapter (0.5.0)
     parallel (1.23.0)
-    parser (3.2.1.0)
+    parser (3.2.2.3)
       ast (~> 2.4.1)
+      racc
     pg (1.4.5)
     prime (0.1.2)
       forwardable
@@ -419,7 +420,7 @@ GEM
     rchardet (1.8.0)
     recaptcha (5.12.3)
       json
-    regexp_parser (2.7.0)
+    regexp_parser (2.8.1)
     responders (3.1.0)
       actionpack (>= 5.2)
       railties (>= 5.2)
@@ -458,7 +459,7 @@ GEM
       rubocop-ast (>= 1.24.1, < 2.0)
       ruby-progressbar (~> 1.7)
       unicode-display_width (>= 2.4.0, < 3.0)
-    rubocop-ast (1.26.0)
+    rubocop-ast (1.29.0)
       parser (>= 3.2.1.0)
     rubocop-capybara (2.17.1)
       rubocop (~> 1.41)
@@ -467,7 +468,7 @@ GEM
     rubocop-performance (1.16.0)
       rubocop (>= 1.7.0, < 2.0)
       rubocop-ast (>= 0.4.0)
-    rubocop-rails (2.17.4)
+    rubocop-rails (2.20.2)
       activesupport (>= 4.2.0)
       rack (>= 1.1)
       rubocop (>= 1.33.0, < 2.0)
@@ -478,7 +479,7 @@ GEM
       rubocop-capybara (~> 2.17)
     rubocop-thread_safety (0.4.4)
       rubocop (>= 0.53.0)
-    ruby-progressbar (1.11.0)
+    ruby-progressbar (1.13.0)
     ruby2_keywords (0.0.5)
     ruby_dig (0.0.2)
     rubyzip (2.3.2)