gbp-buildpackage.groovy.j2: Respect the debian/gbp.conf declaration
This actually allows the swh patched dulwich to build in our ci and be uploaded in our
debian repository [1]
[1]
root@pergamon:/srv/softwareheritage/repository# reprepro ls dulwich dulwich | 0.19.13-1~bpo9~swh+1 | stretch-swh | source dulwich | 0.20.25-2~swh1~bpo10+1 | buster-swh | source dulwich | 0.20.25-2~swh1 | sid | source
Related to T3457