signing tags
Now signed commits are avaiable, next goal is to sign tags.
Is already possible but first step (create the tag buffer content) is not available from libgit2, so needs to be recreated in gitg (not a fuss).
https://github.com/libgit2/libgit2/issues/6293
From UI perspective is just add a check to sign the commit
relates to #317 (closed)