We are merging the “signed” upstream tags as upstream, instead of
using the tarball that doesn’t ship tests.

# Example to import upstream 3.12.4 version
version=3.12.4
# We still use the upstream branch to drop the .gitattributes file from upstream
gbp import-ref --upstream-tag=%\(version%~%-\)s -u$version --debian-branch=upstream
gbp import-ref --upstream-tree=BRANCH -u$version
