set specific ubuntu

Signed-off-by: Tomislav Janjusic <tomislavj@nvidia.com>

Author: janjust

.github/workflows/ompi_mpi4py.yaml

@@ -17,7 +17,7 @@ on:
 
 jobs:
   test:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
     timeout-minutes: 30
     env:
       MPI4PY_TEST_SPAWN: true