This commit removes the publish step in GitHub actions, insteading
folding all functionality into the release build steps. This avoids
having a separately scheduled job after all the release build jobs which
ends up getting delayed for quite a long time given the current
scheduling algorithm.
This involves refactoring the tarball assembly scripts and refactoring the
github asset upload script too. Tarball assembly now manages everything
internally and does platform-specific bits where necessary. The upload
script is restructured to be run in parallel (in theory) and hopefully
catches various errors and tries to not stomp over everyone else's work.
The main trickiness here is handling `dev`, which is less critical for
correctness than than tags themselves.
As a small tweak build-wise the QEMU build for cross-compiled builders
is now cached unlike before where it was unconditionally built, shaving
a minute or two off build time.
Alex Crichton
2b0649c74c