Drop Bionic support

Since victoria cycle, we have moved upstream testing to
Ubuntu Focal (20.04) and so does no Bionic distro in
Xena cycle testing runtime[1]. Grenade jobs also started
running on Focal since victoria was released.

Only thing left was legacy jobs which were not migrated to
Ubuntu Focal in Victoria and as per another community-wide
goal[2], all the lgeacy jobs were suppsoed to be migrated
to zuulv3 native jobs in victoria cycle itself. One of the
pending job was in nova (nova-grenade-multinode) which is also
migrated to zuulv3 native now
- https://review.opendev.org/c/openstack/nova/+/778885

If there is any job running on bionic, we strongly recommend
to migrate it to Ubuntu Focal.

[1] https://governance.openstack.org/tc/reference/runtimes/xena.html
[2] https://governance.openstack.org/tc/goals/selected/victoria/native-zuulv3-jobs.html

Change-Id: I39e38e4a6c2e52dd3822c9fdea354258359a9f53

lib/apache

@@ -93,9 +93,6 @@ function install_apache_uwsgi {
 
     if is_ubuntu; then
         local pkg_list="uwsgi uwsgi-plugin-python3 libapache2-mod-proxy-uwsgi"
-        if [[ "$DISTRO" == 'bionic' ]]; then
-            pkg_list="${pkg_list} uwsgi-plugin-python"
-        fi
         install_package ${pkg_list}
     elif is_fedora; then
         # Note httpd comes with mod_proxy_uwsgi and it is loaded by