testing/singularity: upgrade to 3.6.2
- Ref https://github.com/hpcng/singularity/releases/tag/v3.6.2
- Secfixes: CVE-2020-13845, CVE-2020-13846, and CVE-2020-13847
- Modernize bash completions package creation
- Disable on aarch64 due to segmentation falt during build
- License fix
- Update source url
- Remove patch as it was included mainstream
Edited by Oleg Titov