Fix tarball format output
@smattr pointed out in graphviz.gitlab.io!653 (merged) that the website doesn't display the format of tar files correctly. That's because the JSON release data generated lists their "format"
as "gz"
, or "xz"
. This MR fixes the format data to be "tar.gz"
or "tar.xz"
, as originally intended (based on the JSON data for the oldest releases, which does contain data like "format": "tar.gz"
).