Add Ubuntu 20.04 and Rocky Linux 8 to tested workflows.

Author: geerlingguy

.github/workflows/ci.yml

@@ -41,8 +41,9 @@ jobs:
     strategy:
       matrix:
         distro:
-          - centos8
+          - rockylinux8
           - centos7
+          - ubuntu2004
           - ubuntu1804
           - debian10