Merge pull request #710 from bastelfreak/ubuntu18

Drop EoL Ubuntu 18.04

Author: bastelfreak

metadata.json

@@ -55,7 +55,6 @@
     {
       "operatingsystem": "Ubuntu",
       "operatingsystemrelease": [
-        "18.04",
         "20.04",
         "22.04",
         "24.04"