Update Spack CI

Author: mathomp4

.github/workflows/workflow.yml

@@ -43,3 +43,7 @@ jobs:
       fixture-ref: release/MAPL-v3
       run-mepo-develop: false
       patch-esmf: true
+      # There is some weird issue with spack builds and the install step with
+      # MAPL 3. For now, turn off as we don't need to *run* GEOS.
+      run-install: false
+