Add maven dependency information in README.md

[kiron-mx]

The CmpRaComponent is available on Maven Central. Text proposal:

Maven Dependency

The release versions of CmpRaComponent is available on Maven Central.
Use the following snippet to add the dependency to your Maven project:

<project>
    ...
    <dependencies>
        <dependency>
            <groupId>com.siemens.pki</groupId>
            <artifactId>CmpRaComponent</artifactId>
            <version>4.2.0</version>
        </dependency>
    </dependencies>
    ...
</project>