See: https://github.com/microsoft/vscode/wiki/Commit-Signing
brew install gpg2 gnupg pinentry-mac
mkdir -p ~/.gnupg
echo "pinentry-program $(brew --prefix)/bin/pinentry-mac"
echo "pinentry-program $(brew --prefix)/bin/pinentry-mac" >> ~/.gnupg/gpg-agent.conf
echo "use-agent" >> ~/.gnupg/gpg.conf