Make the gem compatible with ruby 3.4

[satoryu]

No description provided.

[Copilot]

Pull Request Overview

This PR aims to ensure the gem is compatible with Ruby 3.4. The changes include adding dependencies in the gemspec to support the new version and updating the CI workflow to run tests on Ruby 3.4, as well as upgrading the checkout action.

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
rakuten_web_service.gemspec	Added dependencies for 'base64' and 'bigdecimal' to support Ruby 3.4 compatibility.
.github/workflows/ci.yml	Updated the Ruby version matrix to include 3.4 and upgraded the checkout action version.

Comments suppressed due to low confidence (3)

rakuten_web_service.gemspec:20

• Verify if adding 'base64' as a dependency is necessary since it has traditionally been part of the Ruby standard library; if it is required for Ruby 3.4 compatibility, consider adding a clarifying comment.

spec.add_dependency 'base64', '~> 0.2'

rakuten_web_service.gemspec:21

• Confirm that including 'bigdecimal' as a dependency is intended for Ruby 3.4 compatibility, as earlier Ruby versions included it in the standard library.

spec.add_dependency 'bigdecimal', '~> 3.1'

.github/workflows/ci.yml:24

• Ensure that upgrading to actions/checkout@v4 does not introduce any breaking changes in subsequent CI steps.

- uses: actions/checkout@v4