Starting with 4.2.5, we are merging the unsigned upstream tags as
upstream, instead of using the tarball that doesn’t ship tests.

# Example to import upstream 4.2.6 version
version=4.2.6
# We still use the upstream branch to drop the .gitattributes file from upstream
gbp import-ref --upstream-tag=v%\(version%~%-\)s -u$version --debian-branch=upstream
gbp import-ref --upstream-tree=BRANCH -u$version
