Update rubocop-rspec requirement from = 2.20.0 to = 2.21.0 (#82)

Updates the requirements on [rubocop-rspec](https://github.com/rubocop/rubocop-rspec) to permit the latest version.
- [Release notes](https://github.com/rubocop/rubocop-rspec/releases)
- [Changelog](https://github.com/rubocop/rubocop-rspec/blob/master/CHANGELOG.md)
- [Commits](rubocop/rubocop-rspec@v2.20.0...v2.21.0)

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

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Gemfile.lock

@@ -6,7 +6,7 @@ PATH
       rubocop-faker (= 1.1.0)
       rubocop-rails (= 2.19.1)
       rubocop-rake (= 0.6.0)
-      rubocop-rspec (= 2.20.0)
+      rubocop-rspec (= 2.21.0)
 
 GEM
   remote: https://rubygems.org/
@@ -120,7 +120,7 @@ GEM
     nokogiri (1.14.3-x86_64-linux)
       racc (~> 1.4)
     parallel (1.23.0)
-    parser (3.2.2.0)
+    parser (3.2.2.1)
       ast (~> 2.4.1)
     racc (1.6.2)
     rack (2.2.6.4)
@@ -179,9 +179,9 @@ GEM
       rubocop-ast (>= 1.28.0, < 2.0)
       ruby-progressbar (~> 1.7)
       unicode-display_width (>= 2.4.0, < 3.0)
-    rubocop-ast (1.28.0)
+    rubocop-ast (1.28.1)
       parser (>= 3.2.1.0)
-    rubocop-capybara (2.17.1)
+    rubocop-capybara (2.18.0)
       rubocop (~> 1.41)
     rubocop-faker (1.1.0)
       faker (>= 2.12.0)
@@ -192,7 +192,7 @@ GEM
       rubocop (>= 1.33.0, < 2.0)
     rubocop-rake (0.6.0)
       rubocop (~> 1.0)
-    rubocop-rspec (2.20.0)
+    rubocop-rspec (2.21.0)
       rubocop (~> 1.33)
       rubocop-capybara (~> 2.17)
     ruby-progressbar (1.13.0)

boxt_rubocop.gemspec

@@ -32,5 +32,5 @@ Gem::Specification.new do |spec|
   spec.add_dependency "rubocop-faker", "1.1.0"
   spec.add_dependency "rubocop-rails", "2.19.1"
   spec.add_dependency "rubocop-rake", "0.6.0"
-  spec.add_dependency "rubocop-rspec", "2.20.0"
+  spec.add_dependency "rubocop-rspec", "2.21.0"
 end