In GitHub CI, don't put built binaries inside repo.
In GitHub CI, don't put built binaries inside repo.

Putting binaries inside repo will result in vcs.modified=true in the buildinfo,
making the binaries different from those from dl.elv.sh.

Also update the build script to align with https://github.com/elves/up.

elves/elvish,elves/elvish,elves/elvish,elves/elvish,elves/elvish