Plugging the `git` version into the `PROJECT_NUMBER`

I am wondering whether the action can be instructed to use a custom script that simply calls `doxygen` with the `PROJECT_NUMBER` being exported using the `git` version or a tag name.

If not, can this be done otherwise?

Otherwise, and although the action implies that the documentation matches the `HEAD` revision, we do not have any indication of the version that we are looking at.

Thanks for maintaining this tool.