Bump rubocop from 0.67.2 to 0.68.1

Bumps [rubocop](https://github.com/rubocop-hq/rubocop) from 0.67.2 to 0.68.1.
- [Release notes](https://github.com/rubocop-hq/rubocop/releases)
- [Changelog](https://github.com/rubocop-hq/rubocop/blob/master/CHANGELOG.md)
- [Commits](rubocop/rubocop@v0.67.2...v0.68.1)

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

Gemfile.lock

@@ -203,13 +203,12 @@ GEM
       omniauth (~> 1.9)
     orm_adapter (0.5.0)
     parallel (1.17.0)
-    parser (2.6.2.1)
+    parser (2.6.3.0)
       ast (~> 2.4.0)
     pg (1.1.4)
     pry (0.12.2)
       coderay (~> 1.1.0)
       method_source (~> 0.9.0)
-    psych (3.1.0)
     public_suffix (3.0.3)
     puma (3.12.1)
     rack (2.0.7)
@@ -275,11 +274,10 @@ GEM
     rspec-support (3.8.0)
     rspec_junit_formatter (0.4.1)
       rspec-core (>= 2, < 4, != 2.12.0)
-    rubocop (0.67.2)
+    rubocop (0.68.1)
       jaro_winkler (~> 1.5.1)
       parallel (~> 1.10)
       parser (>= 2.5, != 2.5.1.1)
-      psych (>= 3.1.0)
       rainbow (>= 2.2.2, < 4.0)
       ruby-progressbar (~> 1.7)
       unicode-display_width (>= 1.4.0, < 1.6)