This update for singularity fixes the following issues:

Update to new version 3.6.4:

- CVE-2020-15229: Due to insecure handling of path traversal and the lack of path 
  sanitization within unsquashfs, it is possible to overwrite/create files on the
  host filesystem during the extraction of a crafted squashfs filesystem (boo#1177901).

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