Align maven coordinates with JitPack

[tdiesler]

Currently there is some confusion around groupId+artifactId and what jitpack is using. For maven builds, its important that these align.

JitPack releases like this

        <dependency>
            <groupId>com.github.multiformats</groupId>
            <artifactId>java-multiaddr</artifactId>
        </dependency>

which should also be the identity of the artifact in the pom. Alternatively, it may be possible to tweak JitPack to release with identity currently given in the pom.

[ianopolous]

I'm happy to accept a PR on this.

[tdiesler]

It's been sitting here: #11