Usethis: Set RStudio defaults

[hadley]

https://blog.rstudio.com/2020/02/18/rstudio-1-3-preview-configuration/ — eg to not save/load workspace

[jennybc]

Yes, the day has finally arrived that we can do this 💥

[hadley]

{
    "save_workspace": "never",
    "load_workspace": false,
}

[hadley]

And use in use_blank_slate()