Merge pull request #10509 from Icinga/Ubuntu25.04

GHA: add Ubuntu 25.04

Author: julianbrost

.github/workflows/linux.yml

@@ -52,6 +52,7 @@ jobs:
           - ubuntu:22.04
           - ubuntu:24.04
           - ubuntu:24.10
+          - ubuntu:25.04
 
         platform:
           - linux/amd64