CI: Drop very old Ruby versions from matrix

.github/workflows/ci.yml

@@ -18,10 +18,10 @@ jobs:
     steps:
       - uses: actions/checkout@v6
 
-      - name: Set up Ruby 2.7
+      - name: Set up Ruby 3.0
         uses: ruby/setup-ruby@v1
         with:
-          ruby-version: 2.7
+          ruby-version: '3.0'
           bundler-cache: true # 'bundle install' and cache
         env:
           BUNDLE_WITH: lint
@@ -33,7 +33,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        ruby: [ '2.6', '2.7', '3.0', '3.1', '3.2', '3.3' ]
+        ruby: [ '3.0', '3.1', '3.2', '3.3', '3.4', '4.0' ]
 
     steps:
       - uses: actions/checkout@v6

Gemfile

@@ -7,12 +7,12 @@ gemspec
 # Required gems to run all Faraday tests
 
 group :lint, :development do
-  gem 'bundler', '~> 2.0'
-  gem 'rake', '~> 13.0'
-  gem 'rspec', '~> 3.0'
+  gem 'bundler', '>= 2.0'
+  gem 'rake', '>= 13.0'
+  gem 'rspec', '>= 3.0'
   gem 'rubocop', '~> 1.37'
-  gem 'rubocop-packaging', '~> 0.5'
-  gem 'rubocop-performance', '~> 1.0'
+  gem 'rubocop-packaging'
+  gem 'rubocop-performance'
   gem 'simplecov'
-  gem 'webmock', '~> 3.4'
+  gem 'webmock'
 end

spec/faraday/http/adapter_spec.rb

@@ -73,7 +73,7 @@
     let(:conn) do
       conn_options[:ssl] ||= {}
       conn_options[:ssl][:client_cert] ||= OpenSSL::X509::Certificate.new
-      conn_options[:ssl][:private_key] ||= OpenSSL::PKey::RSA.new
+      conn_options[:ssl][:private_key] ||= OpenSSL::PKey::RSA.new(2048)
 
       Faraday.new(remote, conn_options) do |conn|
         conn.request :url_encoded