a note on previous covariate names/storage from hancock et al

[njtierney]

Previously for hancock et al, covariates were stored as so in targets:

  tar_target(covariate_path,
    "data/ir-data-covariates.rds",
    format = "file"
  ),
  covariate_names_raw = read_rds(covariate_path),

  # currently downsampling to speed up initial model fits
  covariate_names = covariate_names_raw[1:10],