piranha: Piranha-micro jar returns no main manifest attribute

Given a project wth this pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>sh.platform.template</groupId>
    <artifactId>piranha</artifactId>
    <packaging>war</packaging>
    <version>1.0.0-SNAPSHOT</version>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <platform.sh.version>2.2.3</platform.sh.version>
    </properties>

    <dependencies>

        <dependency>
            <groupId>jakarta.servlet</groupId>
            <artifactId>jakarta.servlet-api</artifactId>
            <version>4.0.3</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>sh.platform</groupId>
            <artifactId>config</artifactId>
            <version>${platform.sh.version}</version>
        </dependency>
        <dependency>
            <groupId>cloud.piranha</groupId>
            <artifactId>piranha-micro</artifactId>
            <version>20.4.0</version>
        </dependency>
    </dependencies>
    <build>
        <finalName>piranha</finalName>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>

            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-war-plugin</artifactId>
                <version>3.2.3</version>
                <configuration>
                    <failOnMissingWebXml>false</failOnMissingWebXml>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-dependency-plugin</artifactId>
                <version>3.1.1</version>
                <executions>
                    <execution>
                        <phase>package</phase>
                        <goals>
                            <goal>copy</goal>
                        </goals>
                        <configuration>
                            <artifactItems>
                                <artifactItem>
                                    <groupId>cloud.piranha</groupId>
                                    <artifactId>piranha-micro</artifactId>
                                    <version>20.4.0</version>
                                </artifactItem>
                            </artifactItems>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
</project>

When I execute:

mvn clean package
java -jar target/dependency/piranha-micro-20.4.0.jar target/piranha.war 

It returns: no main manifest attribute, in target/dependency/piranha-micro-20.4.0.jar