These directories only need to be set if you are paranoid and want to keep your signing key on removable storage. If you are comfortable leaving the default gpg keyring you just need to keep `gpg.keyname`, `gpg.passphrase` and `gpg.useagent`

Additionally if you will have one and only one gpg key that will be used to sign releases in central you can hardcode the gpg.keyname in to the `pom.xml` and leave just the `gpg.passphrase` for either manual prompt via the agent or providing via `~/.m2/settings.xml` in the profile.

Though if people want to release their own forks of JUnit to their own internal repo they will thank you for leaving `gpg.keyname` as a property.