Explicitly describe the architecture as deprecated,
it remains available as its current alias x86-64-sse41-popcnt
CPUs that support just this instruction set are now years old,
any few years old Intel or AMD CPU supports x86-64-avx2. However,
naming things 'modern' doesn't age well, so instead use explicit names.
Adjust CI accordingly. Wiki, fishtest, downloader done as well.
closes https://github.com/official-stockfish/Stockfish/pull/4691
No functional change.
Github Actions allows us to use up to 20 workers.
This way we can launch multiple different checks
at the same time and optimize the overall time
the CI takes a bit.
closes https://github.com/official-stockfish/Stockfish/pull/4223
No functional change