Source tarball contains a "apache-pulsar" directory instead of "apache-pulsar-adapters"

[eolivelli]

Describe the bug
The release producer is inherited from the main repo (Pulsar) and the configuration of the Maven plugin that creates the source tarball creates a source tarball with a directory named after "apache-pulsar".

We should override the name for this repository

This problem has been reported by @codelipenghui during the VOTE for 2.8.0rc1