dependabot で `workbox-* の pattern を追加

[Pugma]

概要

なぜこの PR を入れたいのか

• workbox-* 関連の dependabot PR が別々に立っていたこと
• これらの パッケージが別ではなく、同一のバージョンで管理されていること

動作確認の手順

CI の pass

UI 変更部分のスクリーンショット

なし

PR を出す前の確認事項

• （機能の追加なら）追加することの合意がチームで取れている
  • 取れていない場合はチェックを外して PR にすれば OK
• 動作確認ができている
• 自分で一度コードを眺めて自分的に問題はなさそう

見てほしいところ・聞きたいことなど

[github-actions]

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Preview (dev) → https://4963-dev.traq-preview.trapti.tech/

[Copilot]

Pull request overview

This PR adds a Dependabot configuration to group workbox-* package updates together, preventing separate PRs for each workbox package and ensuring they are updated together as a cohesive set.

• Adds a new dependency group pattern workbox-* to group all workbox-related packages
• Ensures workbox packages (currently 6 packages: workbox-cacheable-response, workbox-core, workbox-expiration, workbox-precaching, workbox-routing, and workbox-strategies) are updated together

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 60.81%. Comparing base (9f296d7) to head (2c726dc).
⚠️ Report is 67 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4963      +/-   ##
==========================================
- Coverage   61.06%   60.81%   -0.26%     
==========================================
  Files         102      101       -1     
  Lines        2969     2973       +4     
  Branches      614      616       +2     
==========================================
- Hits         1813     1808       -5     
- Misses       1059     1071      +12     
+ Partials       97       94       -3     

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