GitHub Actions の起動イベントに workflow_dispatch を追加する

[zztkm]

• [UPDATE] GitHub Actions の起動イベントに workflow_dispatch を追加

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This pull request includes changes to the GitHub Actions workflow and the project's change log. The most significant changes are the addition of the workflow_dispatch event to the GitHub Actions workflow and the corresponding update to the change log.

• .github/workflows/build.yml: Added the workflow_dispatch event to the GitHub Actions workflow. This allows the workflow to be manually triggered from the GitHub Actions UI.
• CHANGES.md: Updated the change log to reflect the addition of the workflow_dispatch event to the GitHub Actions workflow.

[torikizi]

修正ありがとうございます

[zztkm]

レビューありがとうございます、マージします。