[stable-2.9] Add CentOS 8 to the test matrix (#68025)

* Add CentOS 8 to the test matrix (#63649)

(cherry picked from commit 2a7623dd5c)

* Skip PostgreSQL tests on CentOS 8

The tests in devel have diverged significantly from what is in
stable-2.9. It is easiest to skip these test for CentOS 8 in this branch
since they are still being run in devel.

shippable.yml

@@ -72,6 +72,7 @@ matrix:
     - env: T=freebsd/12.0/1
     - env: T=linux/centos6/1
     - env: T=linux/centos7/1
+    - env: T=linux/centos8/1
     - env: T=linux/fedora30/1
     - env: T=linux/fedora31/1
     - env: T=linux/opensuse15py2/1
@@ -86,6 +87,7 @@ matrix:
     - env: T=freebsd/12.0/2
     - env: T=linux/centos6/2
     - env: T=linux/centos7/2
+    - env: T=linux/centos8/2
     - env: T=linux/fedora30/2
     - env: T=linux/fedora31/2
     - env: T=linux/opensuse15py2/2
@@ -100,6 +102,7 @@ matrix:
     - env: T=freebsd/12.0/3
     - env: T=linux/centos6/3
     - env: T=linux/centos7/3
+    - env: T=linux/centos8/3
     - env: T=linux/fedora30/3
     - env: T=linux/fedora31/3
     - env: T=linux/opensuse15py2/3
@@ -114,6 +117,7 @@ matrix:
     - env: T=freebsd/12.0/4
     - env: T=linux/centos6/4
     - env: T=linux/centos7/4
+    - env: T=linux/centos8/4
     - env: T=linux/fedora30/4
     - env: T=linux/fedora31/4
     - env: T=linux/opensuse15py2/4

test/integration/targets/setup_postgresql_db/tasks/main.yml

@@ -1,3 +1,7 @@
+- name: End play on CentOS 8
+  meta: end_play
+  when: ansible_facts.distribution ~ ansible_facts.distribution_major_version == 'CentOS8'
+
 - name: python 2
   set_fact:
     python_suffix: ""

test/lib/ansible_test/_data/completion/docker.txt

@@ -1,6 +1,7 @@
 default name=quay.io/ansible/default-test-container:1.10.1 python=3.6,2.6,2.7,3.5,3.7,3.8 seccomp=unconfined
 centos6 name=quay.io/ansible/centos6-test-container:1.8.0 python=2.6 seccomp=unconfined
 centos7 name=quay.io/ansible/centos7-test-container:1.8.0 python=2.7 seccomp=unconfined
+centos8 name=quay.io/ansible/centos8-test-container:1.10.0 python=3.6 seccomp=unconfined
 fedora30 name=quay.io/ansible/fedora30-test-container:1.9.2 python=3.7
 fedora31 name=quay.io/ansible/fedora31-test-container:1.11.0 python=3.7
 opensuse15py2 name=quay.io/ansible/opensuse15py2-test-container:1.14.0 python=2.7