chore(deps): update codecov/codecov-action action to v6

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
codecov/codecov-action	action	major	v5 → v6

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Release Notes

codecov/codecov-action (codecov/codecov-action)

v6

Compare Source

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Configuration

📅 Schedule: Branch creation - Between 03:00 AM and 09:59 AM, only on Sunday and Saturday ( * 3-9 * * 0,6 ) in timezone Asia/Tokyo, Automerge - At any time (no schedule defined).

🚦 Automerge: Enabled.

♻ Rebasing: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox.

🔕 Ignore: Close this PR and you won't be reminded about this update again.

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• If you want to rebase/retry this PR, check this box

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.00%. Comparing base (a03b9c8) to head (c8c9221).
⚠️ Report is 33 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #148   +/-   ##
=======================================
  Coverage   95.00%   95.00%           
=======================================
  Files           2        2           
  Lines          40       40           
  Branches        9        9           
=======================================
  Hits           38       38           
  Misses          2        2           

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