Rebuild greatLakesTrLayer from great_lakes_polygon

[chrisholbrook]

Origin of data/greatLakesTrLayer.rda is unknown. Rebuild from data/great_lakes_polygon.rda using make_transition3() and place code in data-raw/great_lakes_transition_layer.r; e.g.,

# x and y res set to roughly match previous version (greatLakesTrLayer)
great_lakes_transition_layer <- make_transition3(great_lakes_polygon, res = c(0.033, 0.011))

# add to (exported) data
usethis::use_data(great_lakes_transition_layer, overwrite = TRUE)

Also add tests for new data object and make_transition3().