Drop EoL Ubuntu 18.04 support

bastelfreak · bastelfreak · commit 1cd325e0e0b5 · 2024-02-08T14:46:41.000+01:00
This is EoL since April 2023.
diff --git a/metadata.json b/metadata.json
@@ -55,7 +55,6 @@
     {
       "operatingsystem": "Ubuntu",
       "operatingsystemrelease": [
-        "18.04",
         "20.04",
         "22.04"
       ]
