Updated production release

We had previously not used the github release mechanisms but linked to tarballs from our website https://www.p4est.org/, which we still do.

This is only the second time we create a github release. The libtool .so version is 3:0:0.

Please see the release notes for details.

Previous production release

This is a release of 2023 that has been tracked previously as a draft. It is purely for reference.

We had previously not used the github release mechanisms but linked to tarballs from our website https://www.p4est.org/.

This was the first time we create a github release. The libtool API version is 2:0:0.