actions-mutex is duplicated, use `concurrency` instead of it

[koron]

Actionsに次のようなメッセージが表示されていた。
対応したほうがよさそう。

generate

shogo82148/actions-mutex is no longer maintained. Please consider use official support for limiting concurrency. https://github.com/shogo82148/actions-mutex#official-concurrency-support-on-github-actions

https://github.com/shogo82148/actions-mutex#official-concurrency-support-on-github-actions

On April 19, 2021, GitHub launched support for limiting concurrency in the workflow files. Please consider to use this feature.

GitHub Actions: Limit workflow run or job concurrency