Ruby 3.4 support (#8)

* Add Ruby 3.4 to CI matrix; remove unsupported Rubies

* Add base64 gem as dependency; bump minimum Ruby version to 2.7

.github/workflows/ci.yml

@@ -8,14 +8,14 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest, macos-latest]
-        ruby: [2.4, 2.5, 2.6, 2.7, '3.0', 3.1, 3.2, 3.3, jruby, truffleruby]
+        ruby: [2.7, '3.0', 3.1, 3.2, 3.3, 3.4, jruby, truffleruby]
 
     runs-on: ${{ matrix.os }}
 
     name: Test against ${{ matrix.ruby }} on ${{ matrix.os }}
 
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Set up Ruby
       uses: ruby/setup-ruby@v1
       with:

README.md

@@ -103,7 +103,7 @@ signatures:
 
 ## Supported rubies
 
-This gem is tested against and supports Ruby 2.4 through 3.3, JRuby and
+This gem is tested against and supports Ruby 2.7 through 3.3, JRuby and
 TruffleRuby.
 
 ## Development

aws-cognito-srp.gemspec

@@ -20,9 +20,10 @@ Gem::Specification.new do |spec|
   end
   spec.require_paths = ["lib"]
 
-  spec.required_ruby_version = '>= 2.4.0'
+  spec.required_ruby_version = '>= 2.7.0'
 
   spec.add_dependency "aws-sdk-cognitoidentityprovider"
+  spec.add_dependency "base64"
 
   spec.add_development_dependency "bundler", "~> 2.2"
   spec.add_development_dependency "rake", "~> 13.0"