Starting with 1.2.0, we are merging the signed upstream tags as
upstream, instead of using the tarball that doesn’t ship tests.

# Example to import upstream 1.2.1 version
$ version=1.2.1
# We still use the upstream branch to drop the .gitattributes file from upstream
$ git checkout upstream
$ gbp import-ref --upstream-tag=v%\(version%~%-\)s -u$version --debian-branch=upstream
$ git checkout master
$ gbp import-ref --upstream-tree=BRANCH -u$version
