name tar / zip contents based on project name

It is very nice that a tar or zip file can be downloaded based on a tag name:

https://bitbucket.org/eradman/ephemeralpg/get/${TAGNAME}.tar.gz

But the when I untar the file it creates a directory which some users find annoying:

eradman-ephemeralpg-d4a43b733252

Is it possible to simply name the directory based on the tag? This then becomes something like:

ephemeralpg-1.8