This update for singularity fixes the following issues:

- New version 3.6.0. This version introduces a new signature format 
for SIF images, and changes to the signing / verification code to address
the following security problems:
  - CVE-2020-13845, boo#1174150
  In Singularity 3.x versions below 3.6.0, issues allow the ECL to 
  be bypassed by a malicious user.
  - CVE-2020-13846, boo#1174148
  In Singularity 3.5 the --all / -a option to singularity verify 
  returns success even when some objects in a SIF container are not signed, 
  or cannot be verified.
  - CVE-2020-13847, boo#1174152
  In Singularity 3.x versions below 3.6.0, Singularity's sign and verify 
  commands do not sign metadata found in the global header or data object 
  descriptors of a SIF file, allowing an attacker to cause unexpected 
  behavior. A signed container may verify successfully, even when it has 
  been modified in ways that could be exploited to cause malicious behavior.

- New features / functionalities
  - A new '--legacy-insecure' flag to verify allows verification of SIF
  signatures in the old, insecure format.
  - A new '-l / --logs' flag for instance list that shows the paths 
  to instance STDERR / STDOUT log files.
  - The --json output of instance list now include paths to 
  STDERR / STDOUT log files.
  - Singularity now supports the execution of minimal Docker/OCI
  containers that do not contain /bin/sh, e.g. docker://hello-world.
  - A new cache structure is used that is concurrency safe on a filesystem that
  supports atomic rename. If you downgrade to Singularity 3.5 or older after
  using 3.6 you will need to run singularity cache clean.
  - A plugin system rework adds new hook points that will allow the
  development of plugins that modify behavior of the runtime. An image driver
  concept is introduced for plugins to support new ways of handling image and
  overlay mounts. Plugins built for <=3.5 are not compatible with 3.6.
  - The --bind flag can now bind directories from a SIF or ext3 image into a
  container.
  - The --fusemount feature to mount filesystems to a container via FUSE
  drivers is now a supported feature (previously an experimental hidden flag).
  - This permits users to mount e.g. sshfs and cvmfs filesystems to the
  container at runtime.
  - A new -c/--config flag allows an alternative singularity.conf to be
  specified by the root user, or all users in an unprivileged installation.
  - A new --env flag allows container environment variables to be set via the
  Singularity command line.
  - A new --env-file flag allows container environment variables to be set from
  a specified file.
  - A new --days flag for cache clean allows removal of items older than a
  specified number of days. Replaces the --name flag which is not generally
  useful as the cache entries are stored by hash, not a friendly name.

- Changed defaults / behaviours
 - New signature format (see security fixes above).
 - Fixed spacing of singularity instance list to be dynamically changing 
 based off of input lengths instead of fixed number of spaces to account
 for long instance names.
 - Environment variables prefixed with SINGULARITYENV_ always take
 precedence over variables without SINGULARITYENV_ prefix.
 - The %post build section inherits environment variables from the base image.
 - %files from ... will now follow symlinks for sources that are directly
 specified, or directly resolved from a glob pattern. It will not follow
 symlinks found through directory traversal. This mirrors Docker multi-stage
 COPY behaviour.
 - Restored the CWD mount behaviour of v2, implying that CWD path is not recreated
 inside container and any symlinks in the CWD path are not resolved anymore to
 determine the destination path inside container.
 - The %test build section is executed the same manner as singularity test image.
 --fusemount with the container: default directive will foreground the FUSE
 process. Use container-daemon: for previous behavior.

- Deprecate -a / --all option to sign/verify as new signature behavior 
  makes this the default.
- For more information about upstream changes, please check:
  https://github.com/hpcng/singularity/blob/master/CHANGELOG.md
- Removed --name flag for cache clean; replaced with --days.

This update was imported from the openSUSE:Leap:15.2:Update update project.