pin version of ubuntu in xios build

Author: mo-marqh

.github/workflows/buildTest.yml

@@ -9,7 +9,7 @@ on:
 jobs:
   build_test:
     name: build test
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
     strategy:
       matrix:
         version: [XIOS/trunk@2252, XIOS2/trunk, XIOS3/trunk]