[why]
Because we want to use Node 20 etc pp
[how]
Check for breaking changes and update.
Also replace checkout-files by checkout with sparse-checkout; as they
semselves encourage people to do.
action-gh-release has been updated to Node 20 but has not been released
with the change, so we access the latest version directly by hash.
[note]
Of course this is unchecked... what can ge wrong! 😬
Signed-off-by: Fini Jastrow <ulf.fini.jastrow@desy.de>