main/xen: security fixes for XSA-317, XSA-319, XSA-321, XSA-327 and XSA-328
Fixes CVEs:
- CVE-2020-15566
- CVE-2020-15563
- CVE-2020-15565
- CVE-2020-15564
- CVE-2020-15567
At 20:30 UTC, gitlab will be upgraded to 17.9 and will be briefly unavailable.
Fixes CVEs: