import improvements from GPUJPEG - summary:
- LABEL - replace ' ' with %20 (will get to URL)
- use while instead of for..seq
- cat json file directly (avoid interpretting \n and \r that XSI-compilant
echo, as in dash, does)
- cat really the $json file, don't print its name
- wrap long lines + early return in while-loop
The rewrite of `for n in \`seq` may be perhaps a bit controversal
(with while is less readable) but technically POSIX doesn't specify the
seq comand.
- upload assets with script [nightly]
- remove unneeded Windows runner components (Android, dotnet) to free up
space (namely for Qt)
- no timeout for pacman (sometimes failed)
