GPGの鍵でGitのコミットに署名する
Ref: Telling Git about your signing key - GitHub Docs https://docs.github.com/en/authentication/managing-commit-signature-verification/telling-git-about-your-signing-key
code:how.sh
gpg --list-secret-keys --keyid-format=long
git config --global user.signingkey 5E87897955EE40BE!
git config --global commit.gpgsign true