Updates a metadatafile
Examples
if (FALSE) { # \dontrun{
update_metadata_file("model/nonmem/run001.mod", tags = "key model")
update_metadata_file("model/nonmem/run004.mod", tags = "key model", based_on = "1002")
model <- read_model("model/nonmem/run001.mod")
update_metadata_file(model, tags = "key model")
} # }