.settings.xml

<settings xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://maven.apache.org/SETTINGS/1.0.0" xsi:schemalocation="http://maven.apache.org/SETTINGS/1.0.0
                      http://maven.apache.org/xsd/settings-1.0.0.xsd">
    <servers>
        <server>
            <!-- Maven Central Deployment -->
            <id>central</id>
            <username>${env.MAVEN_CENTRAL_USERNAME}</username>
            <password>${env.MAVEN_CENTRAL_PASSWORD}</password>
        </server>
        <server>
            <id>gpg.passphrase</id>
            <passphrase>${env.MAVEN_GPG_PASSPHRASE}</passphrase>
        </server>
    </servers>
</settings>