diff --git a/.github/workflows/ruby.yml b/.github/workflows/ruby.yml
index e940a81..e210e42 100644
--- a/.github/workflows/ruby.yml
+++ b/.github/workflows/ruby.yml
@@ -13,37 +13,46 @@ jobs:
           - macos
           - windows
         ruby:
-          - 2.1
-          - 2.2
-          - 2.3
-          - 2.4
-          - 2.5
-          - 2.6
-          - 2.7
+          - '2.1'
+          - '2.2'
+          - '2.3'
+          - '2.4'
+          - '2.5'
+          - '2.6'
+          - '2.7'
           - '3.0'
-          - 3.1
-          - 3.2
-          - 3.3
-          - 3.4.0-preview1
-          - head
-          - jruby
-          - jruby-head
-          - truffleruby
-          - truffleruby-head
-          - mingw
+          - '3.1'
+          - '3.2'
+          - '3.3'
+          - '3.4'
+          - '3.5.0-preview1'
+          - 'head'
+          - 'jruby'
+          - 'jruby-head'
+          - 'truffleruby'
+          - 'truffleruby-head'
+          - 'mingw'
         exclude:
-          - { os: ubuntu,  ruby: 2.1 }
-          - { os: ubuntu,  ruby: 2.2 }
-          - { os: ubuntu,  ruby: mingw }
-          - { os: macos,   ruby: mingw }
-          - { os: macos,   ruby: 2.1 }
-          - { os: macos,   ruby: 2.2 }
-          - { os: macos,   ruby: 2.3 }
-          - { os: macos,   ruby: 2.4 }
-          - { os: macos,   ruby: 2.5 }
-          - { os: windows, ruby: truffleruby }
-          - { os: windows, ruby: truffleruby-head }
-          - { os: windows, ruby: 3.4.0-preview1 }
+          - { os: ubuntu,  ruby: '2.1' }
+          - { os: ubuntu,  ruby: '2.2' }
+          - { os: ubuntu,  ruby: '2.5' }
+          - { os: ubuntu,  ruby: '2.6' }
+          - { os: ubuntu,  ruby: 'mingw' }
+          - { os: macos,   ruby: 'mingw' }
+          - { os: macos,   ruby: '2.1' }
+          - { os: macos,   ruby: '2.2' }
+          - { os: macos,   ruby: '2.3' }
+          - { os: macos,   ruby: '2.4' }
+          - { os: macos,   ruby: '2.5' }
+          - { os: macos,   ruby: '2.6' }
+          - { os: windows, ruby: 'truffleruby' }
+          - { os: windows, ruby: 'truffleruby-head' }
+          - { os: windows, ruby: '2.2' }
+          - { os: windows, ruby: '2.3' }
+          - { os: windows, ruby: '2.5' }
+          - { os: windows, ruby: '2.6' }
+          - { os: windows, ruby: 'head' }
+          - { os: windows, ruby: '3.5.0-preview1' }
 
     runs-on: ${{ matrix.os }}-latest
 
@@ -69,11 +78,13 @@ jobs:
           - ubuntu-20.04
           - macos-13
         ruby:
-          - 2.1
-          - 2.2
-          - 2.3
-          - 2.4
-          - 2.5
+          - '2.1'
+          - '2.2'
+          - '2.3'
+          - '2.4'
+          - '2.5'
+        exclude:
+          - { os: macos-13,  ruby: '2.5' }
 
     runs-on: ${{ matrix.os }}
 
diff --git a/bcrypt.gemspec b/bcrypt.gemspec
index c425529..3328401 100644
--- a/bcrypt.gemspec
+++ b/bcrypt.gemspec
@@ -14,6 +14,8 @@ Gem::Specification.new do |s|
 
   s.add_development_dependency 'rake-compiler', '~> 1.2.0'
   s.add_development_dependency 'rspec', '>= 3'
+  s.add_development_dependency 'benchmark'
+  s.add_development_dependency 'rdoc'
 
   s.rdoc_options += ['--title', 'bcrypt-ruby', '--line-numbers', '--inline-source', '--main', 'README.md']
   s.extra_rdoc_files += ['README.md', 'COPYING', 'CHANGELOG', *Dir['lib/**/*.rb']]