update BM `PRJ` files in `inst/ext_data` to ogs6.4.0
The BM related PRJ files in inst/ext_data are related to ogs6.3.3.
These need to be updated to ogs6.4.0 as they are used in tests test-sim_utils.R as well as in examples.
The BM related PRJ files in inst/ext_data are related to ogs6.3.3.
These need to be updated to ogs6.4.0 as they are used in tests test-sim_utils.R as well as in examples.