sysutils/ansible28: Update to 2.8.20

Changes: https://github.com/ansible/ansible/blob/stable-2.8/changelogs/CHANGELOG-v2.8.rst#v2-8-20
MFH: 2021Q2
Security: 50ec3a01-ad77-11eb-8528-8c164582fbac
Security: CVE-2020-10744

(cherry picked from commit 15ecc1948909aa97bb87df303f83ec398a2c91b4)