Bump all distributions to stable versions
Use Alpine 3.14.0 and 3.15.0; Debian 10.11 and 11.2; Fedora 34 and 35; and Ubuntu 18.04 and 20.04.
In Debian, fix package names involving python2. In Ubuntu, do not use the -updates repository (same as Debian).
(This was tested locally: make images
builds all container images successfully.)
Edited by David Ward