chore(deps): update actions/stale action to v8

[renovate[bot]]

This PR contains the following updates:

Package	Type	Update	Change
actions/stale	action	major	v7 -> v8

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Release Notes

actions/stale

### [`v8`](https://togithub.com/actions/stale/compare/v7...v8) [Compare Source](https://togithub.com/actions/stale/compare/v7...v8)

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Configuration

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[codecov[bot]]

Codecov Report

Patch and project coverage have no change.

Comparison is base (bf54f3f) 82.60% compared to head (b275361) 82.60%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #192 +/- ## ======================================= Coverage 82.60% 82.60% ======================================= Files 1 1 Lines 23 23 Branches 5 5 ======================================= Hits 19 19 Misses 3 3 Partials 1 1 ``` Help us with your feedback. Take ten seconds to tell us [how you rate us](https://about.codecov.io/nps?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Shuhei+Hayashibara). Have a feature suggestion? [Share it here.](https://app.codecov.io/gh/feedback/?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Shuhei+Hayashibara)

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