Bump rubocop from 1.30.1 to 1.31.0

Bumps [rubocop](https://github.com/rubocop/rubocop) from 1.30.1 to 1.31.0.
- [Release notes](https://github.com/rubocop/rubocop/releases)
- [Changelog](https://github.com/rubocop/rubocop/blob/master/CHANGELOG.md)
- [Commits](rubocop/rubocop@v1.30.1...v1.31.0)

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

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

Gemfile

@@ -1,3 +1,3 @@
 source 'https://rubygems.org'
 
-gem 'rubocop', '1.30.1', require: false
+gem 'rubocop', '1.31.0', require: false

Gemfile.lock

@@ -8,7 +8,7 @@ GEM
     rainbow (3.1.1)
     regexp_parser (2.5.0)
     rexml (3.2.5)
-    rubocop (1.30.1)
+    rubocop (1.31.0)
       parallel (~> 1.10)
       parser (>= 3.1.0.0)
       rainbow (>= 2.2.2, < 4.0)
@@ -20,14 +20,14 @@ GEM
     rubocop-ast (1.18.0)
       parser (>= 3.1.1.0)
     ruby-progressbar (1.11.0)
-    unicode-display_width (2.1.0)
+    unicode-display_width (2.2.0)
 
 PLATFORMS
   ruby
   x86_64-linux
 
 DEPENDENCIES
-  rubocop (= 1.30.1)
+  rubocop (= 1.31.0)
 
 BUNDLED WITH
    2.2.22