Make the gem compatible with ruby 3.4

Author: satoryu

.github/workflows/ci.yml

@@ -13,15 +13,15 @@ jobs:
     strategy:
       matrix:
         ruby-version:
-          - 2.7
           - "3.0"
           - 3.1
           - 3.2
           - 3.3
+          - 3.4
           - head
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: ruby/setup-ruby@v1
         env:
           BUNDLE_WITHOUT: vscode

rakuten_web_service.gemspec

@@ -17,7 +17,10 @@ Gem::Specification.new do |spec|
   spec.require_paths = ['lib']
   spec.required_ruby_version = '>= 2.7.0'
 
+  spec.add_dependency 'base64', '~> 0.2'
+  spec.add_dependency 'bigdecimal', '~> 3.1'
   spec.add_dependency 'json', '~> 2.3'
+
   spec.add_development_dependency 'bundler'
   spec.add_development_dependency 'debug'
   spec.add_development_dependency 'rake', '~> 13.0'