fix: packages: mpi: require: mpich @4.2.1 -fortran

Author: wdconinc

spack-environment/packages.yaml

@@ -266,7 +266,11 @@ packages:
     - '@2.0.18:'
   mpi:
     require:
-    - openmpi
+    - mpich
+  mpich:
+    require:
+    - '@4.2.1'
+    - -fortran
   nlohmann-json:
     require:
     - '@3.11.2:'