Bump rubocop from 0.60.0 to 0.75.0

Bumps [rubocop](https://github.com/rubocop-hq/rubocop) from 0.60.0 to 0.75.0.
- [Release notes](https://github.com/rubocop-hq/rubocop/releases)
- [Changelog](https://github.com/rubocop-hq/rubocop/blob/master/CHANGELOG.md)
- [Commits](https://github.com/rubocop-hq/rubocop/compare/v0.60.0...v0.75.0)

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

Gemfile

@@ -96,7 +96,7 @@ group :development do
   gem "capistrano3-delayed-job", "~> 1.7.3"
   gem "erb_lint", require: false
   gem "mdl", "~> 0.5.0", require: false
-  gem "rubocop", "~> 0.60.0", require: false
+  gem "rubocop", "~> 0.75.0", require: false
   gem "rubocop-rspec", "~> 1.35.0", require: false
   gem "rvm1-capistrano3", "~> 1.4.0", require: false
   gem "scss_lint", "~> 0.55.0", require: false

Gemfile.lock

@@ -387,7 +387,6 @@ GEM
       activerecord (>= 4.2)
       activesupport (>= 4.2)
       arel (>= 6)
-    powerpack (0.1.2)
     public_suffix (4.0.1)
     puma (4.1.1)
       nio4r (~> 2.0)
@@ -460,14 +459,13 @@ GEM
       rspec-mocks (~> 3.8.0)
       rspec-support (~> 3.8.0)
     rspec-support (3.8.0)
-    rubocop (0.60.0)
+    rubocop (0.75.0)
       jaro_winkler (~> 1.5.1)
       parallel (~> 1.10)
-      parser (>= 2.5, != 2.5.1.1)
-      powerpack (~> 0.1)
+      parser (>= 2.6)
       rainbow (>= 2.2.2, < 4.0)
       ruby-progressbar (~> 1.7)
-      unicode-display_width (~> 1.4.0)
+      unicode-display_width (>= 1.4.0, < 1.7)
     rubocop-rspec (1.35.0)
       rubocop (>= 0.60.0)
     ruby-progressbar (1.10.1)
@@ -550,7 +548,7 @@ GEM
       thread_safe (~> 0.1)
     uglifier (4.1.19)
       execjs (>= 0.3.0, < 3)
-    unicode-display_width (1.4.1)
+    unicode-display_width (1.6.0)
     unicorn (5.4.1)
       kgio (~> 2.6)
       raindrops (~> 0.7)
@@ -648,7 +646,7 @@ DEPENDENCIES
   rinku (~> 2.0.2)
   rollbar (~> 2.18.0)
   rspec-rails (~> 3.8)
-  rubocop (~> 0.60.0)
+  rubocop (~> 0.75.0)
   rubocop-rspec (~> 1.35.0)
   rvm1-capistrano3 (~> 1.4.0)
   sass-rails (~> 5.0, >= 5.0.4)