Make mixed model test data permanent to ensure reproducibility

To ensure that tests on different platforms work on the same data, the
mixed modelling test data previosly generated in
tests/testthat/setup_script.R were generated once using the script in
inst/dataset/generation/ds_mixed.R, and are now distributed with the
package.

1 files changed, 0 insertions, 0 deletions

diff --git a/data/ds_mixed.rda b/data/ds_mixed.rda
new file mode 100644
index 00000000..cf9f6463
--- /dev/null
+++ b/data/ds_mixed.rda