GHA: Retry with 'Rmpi' as a dependency - take 7

Author: HenrikBengtsson

.github/workflows/R-CMD-check.yaml

@@ -161,6 +161,7 @@ jobs:
         if: runner.os != 'macOS'
         env:
           NOT_CRAN: true
+	  OMPI_MCA_rmaps_base_oversubscribe: 1
         run: |
           install.packages(c("Rmpi", "snow"))
           future:::testme("mpi")