sylabs/singularity: Singularity 3.0.2 release candidate 2

Seasons greetings Singularity community! The Singularity elves have been hard at work and the holidays are coming a little early this year! :gift: This is the second release candidate for Singularity 3.0.2! Just in time for holiday vacations! Woot! So pour some hot cocoa, light some candles, and spend a evening (or two) testing your favorite container platform! This release candidate fixes a ton of bugs. Here are some highlights: Added the --docker-login flag to enable interactive authentication with docker registries Added support for pulling directly from HTTP and HTTPS Made minor improvements to RPM packaging and added basic support for alpine packaging The $SINGULARITY_NOHTTPS,$SINGULARITY_TMPDIR, and $SINGULARITY_DOCKER_USERNAME/$SINGULARITY_DOCKER_PASSWORD environment variables are now correctly respected Pulling from a private shub registry now works as expected Running a container with --network="none" no longer incorrectly fails with an error message Commands now correctly return 1 when incorrectly executed without arguments Progress bars no longer incorrectly display when running with --quiet or --silent Contents of 91-environment.sh file are now displayed if appropriate when running inspect --environment Please take it for a spin, see what works, and report what doesn't! As always, please report any bugs to: https://github.com/sylabs/singularity/issues/new If you think that you've discovered a security vulnerability please report it to: security@sylabs.i