It would help to have the Confluent Maven repository declared in the POM

[ginaluca]

Hi,
I just cloned the project to extend some of its images and at the first attempt the Maven build failed because the common-docker parent could not be found. I made it succeed by adding the Confluent repository, which I knew from some other project, to the POM:

<repositories>
    <repository>
        <id>confluent</id>
        <name>Confluent</name>
        <url>https://packages.confluent.io/maven/</url>
    </repository>
</repositories>

I assume that developers who work regularly with this project have already all the necessary Confluent projects checked out on their computer, so they don't need this. It would be a great help for a beginner though.