[ci] Downgrade ansible on Ubuntu 20.04

Author: nemesifier

.github/workflows/ci.yml

@@ -46,6 +46,11 @@ jobs:
           pip install -U pip wheel setuptools
           pip install -r requirements-test.txt
 
+      - name: [ubuntu2004] Downgrade ansible
+        if: matrix.distro == 'ubuntu2004'
+        run: |
+          pip install "ansible-core<2.19"
+
       - name: Install Ansible Galaxy dependencies
         run: ansible-galaxy collection install "community.general:>=3.6.0"