My attempt at using rust-build/rust-build.action for release builds
(from bf21e65c5d) initially seemed promising. However, the produced
musl binary build segfaulted on my Debian machine. I don't know about
the Mac and Windows binaries. I then tried switching to building with
a vendored OpenSSL (cac93e2793), but then the build started failing
(https://github.com/martinvonz/jj/actions/runs/1978730621). I couldn't
figure out why it failed, so I decided to do the build in a more
manual way (without rust-build/rust-build.action), based on
https://github.com/gitext-rs/git-stack/blob/main/.github/workflows/post-release.yml
(thanks to @epage for the example and to @arxanas for the link). I
could simplify it a bit because I'm currently doing the releases via
the GitHub UI (epage's original triggers the release when a tag has
been pushed, IIUC). Let's hope that it works this time.
