CI: update linux 4c from ubuntu 20 to ubuntu 22

Author: marcoieni

src/ci/github-actions/jobs.yml

@@ -5,7 +5,7 @@ runners:
     env: { }
 
   - &job-linux-4c
-    os: ubuntu-20.04
+    os: ubuntu-22.04
     # Free some disk space to avoid running out of space during the build.
     free_disk: true
     <<: *base-job