macOS packages now include completion files for elvish and fish shells
(#221, @TymekDev).
rig available --list-distros output now includes PPM support, whether
the a distro is retired, the EOL and in the JSON format also the last
R version for that distro.
rig add is now better at detecting PPM support for new Linux
distribution versions. In particular, new Linux distribution releases
do not need a rig update to learn about PPM support. Relatedly,
rig system detect-platform now does not report PPM support.
Use rig available --list-distros to see which Linux distributions have
PPM binaries.
rig run now exits with the exit code of the R process (#261).
Custom certificates via the SSL_CERT_FILE environment variable
work again (#227).
rig library default does not crash now (#240).
rig now uses a better way to get the user's home directory, that works
on systems without an /etc/passwd database (#228).
