CC-2264: Pin maven-site-plugin to a specific version
CC-2264: Pin maven-site-plugin to a specific version

We implicitly determine the version of the `maven-site-plugin`, but recently an incompatible 3.x version was published and is causing this build to fail. Pinning this to 3.7.1 across multiple branches.

confluentinc/camus,confluentinc/camus