This switches the 'remotes/origin/HEAD' and uses the current HEAD of the
current checked out git repo.
Revised the sed rule that is transforming (to be more specific on the
matching regex /-\d+-g/ than just the first /-/):
8.3.530-7-gb64321d4 => 8.3.530+7-gb64321d4 (replace first '-' with '+'
to indicate it is tag plus this many commits)
8.3.530 => 8.3.530 (no change)
This switches to the 'continuous' tag release, that will auto update.
This broke the very old AppImage7 tool since that release not return
HTTP/404. But I updated all to use their current recommendation.