Update rubocop requirement from = 0.90.0 to = 0.91.0 (#2122)

Updates the requirements on [rubocop](https://github.com/rubocop-hq/rubocop) to permit the latest version.
- [Release notes](https://github.com/rubocop-hq/rubocop/releases)
- [Changelog](https://github.com/rubocop-hq/rubocop/blob/master/CHANGELOG.md)
- [Commits](rubocop/rubocop@v0.90.0...v0.91.0)

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

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

Gemfile.lock

@@ -27,16 +27,16 @@ GEM
     rake (13.0.1)
     regexp_parser (1.7.1)
     rexml (3.2.4)
-    rubocop (0.90.0)
+    rubocop (0.91.0)
       parallel (~> 1.10)
       parser (>= 2.7.1.1)
       rainbow (>= 2.2.2, < 4.0)
       regexp_parser (>= 1.7)
       rexml
-      rubocop-ast (>= 0.3.0, < 1.0)
+      rubocop-ast (>= 0.4.0, < 1.0)
       ruby-progressbar (~> 1.7)
       unicode-display_width (>= 1.4.0, < 2.0)
-    rubocop-ast (0.3.0)
+    rubocop-ast (0.4.0)
       parser (>= 2.7.1.4)
     ruby-progressbar (1.10.1)
     simplecov (0.17.1)
@@ -58,7 +58,7 @@ DEPENDENCIES
   minitest (= 5.14.2)
   pry (= 0.13.1)
   rake (= 13.0.1)
-  rubocop (= 0.90.0)
+  rubocop (= 0.91.0)
   simplecov (= 0.17.1)
   test-unit (= 3.3.6)
   timecop (= 0.9.1)

faker.gemspec

@@ -32,7 +32,7 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency('minitest', '5.14.2')
   spec.add_development_dependency('pry', '0.13.1')
   spec.add_development_dependency('rake', '13.0.1')
-  spec.add_development_dependency('rubocop', '0.90.0')
+  spec.add_development_dependency('rubocop', '0.91.0')
   spec.add_development_dependency('simplecov', '0.17.1')
   spec.add_development_dependency('test-unit', '3.3.6')
   spec.add_development_dependency('timecop', '0.9.1')