Merge pull request #2920 from alphagov/dependabot/bundler/gds-api-ada… · alphagov/search-api@984c103

Node.js 16 actions are deprecated. Please update the following actions to use Node.js 20: actions/checkout@v3. For more information see: https://github.blog/changelog/2023-09-22-github-actions-transitioning-from-node-16-to-node-20/.