ci: use ubuntu-22.04 for visual tests for now

Author: larpon

.github/workflows/ci_visual_tests.yml

@@ -15,7 +15,7 @@ concurrency:
 jobs:
 
   ubuntu-latest-visual-tests:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
     timeout-minutes: 20
     env:
       VFLAGS: -cc tcc -no-retry-compilation -d sdl_memory_no_gc