CI: Add ArchLinux, Debian Bullseye and CentOS Stream 8 (#301)

* Add ArchLinux, Debian Bullseye and CentOS Stream 8 to CI.

* Fixes.

tests/utils/shippable/linux-community.sh

@@ -0,0 +1,19 @@
+#!/usr/bin/env bash
+
+set -o pipefail -eux
+
+declare -a args
+IFS='/:' read -ra args <<< "$1"
+
+image="${args[1]}"
+python="${args[2]}"
+
+if [ "${#args[@]}" -gt 3 ]; then
+    target="shippable/posix/group${args[3]}/"
+else
+    target="shippable/posix/"
+fi
+
+# shellcheck disable=SC2086
+ansible-test integration --color -v --retry-on-error "${target}" ${COVERAGE:+"$COVERAGE"} ${CHANGED:+"$CHANGED"} ${UNSTABLE:+"$UNSTABLE"} \
+    --docker "quay.io/ansible-community/test-image:${image}" --python "${python}"