chore: Add data-raw for simplerspec_opus data set

data-raw/opus/.gitkeep

+ 

data-raw/simplerspec_opus.R

+## code to prepare `simplerspec_opus` dataset goes here
+
+simplerspec_opus <- file.path(usethis::proj_path(), "data-raw", "opus") |>
+  dir(full.names = TRUE) |>
+  simplerspec::read_opus_univ() |>
+  simplerspec::gather_spc(spc_types = "spc") |>
+  simplerspec::resample_spc(wn_lower = 4000, wn_upper = 11500, wn_interval = 4) |>
+  simplerspec::average_spc() |>
+  simplerspec::preprocess_spc(select = "custom", custom_function = "spc_raw")
+
+usethis::use_data(simplerspec_opus, overwrite = TRUE)