Use previous version of Ubuntu for tests to avoid interference between Plesk, Docker and systemd

Author: sibprogrammer

.github/workflows/test.yml

@@ -4,7 +4,7 @@ on: [push]
 
 jobs:
   test:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     steps:
       - uses: actions/checkout@v3
       - run: docker-compose run tests