Merge branch 'ubuntu20' into 'master'

reverse-proxy: Fix für Ubuntu 20.04

See merge request !28

reverse-proxy/tasks/main.yml

 - name: Install nginx and certbot
   apt:
-    pkg: [ 'python-certbot-nginx', 'nginx' ]
+    pkg: [ 'python3-certbot-nginx', 'nginx' ]
 
 - name: Copy Nginx config files
   template: