The code path is now adequately tested in CI with try-release.yml. This
means it will no longer be automatically tested locally with `./t.sh`,
but it can be manually tested locally with `./tools/make-assets.sh`.
Also, to ensure CI has similar coverage to the old make-artifacts phase,
change make-deb.sh to make-assets.sh, and have it make all of rpm, deb,
and tar.
Change release.yml so it uploads the .tar.gz as well as the .deb.
Jacob Hoffman-Andrews