Universal release build for Linux

[lionel-]

Follow up to #67.

Looks like we can supply our own build script to cargo dist via the build-command field of dist.toml, so we should be able to use the same approach we did in Ark (posit-dev/ark#486) to create a Linux build that works regardless of the glibc version. We just need to look at the arch triple and use cargo zigbuild for linux targets.