add .Rprofile

[lnnrtwttkhn]

this add the .Rprofile file which allows auto-activating renv in RStudio.

this results in renv giving this useful output, prompting the user to install packages using renv::restore():

# Bootstrapping renv 1.0.0 ---------------------------------------------------
- Downloading renv ... OK
- Installing renv  ... OK

- Project '~/edu/berd-reproducible-research-course' loaded. [renv 1.0.0]
- None of the packages recorded in the lockfile are installed.
- Using `renv::restore()` to restore the project library.
Do you want to proceed? [Y/n]: Y

The following package(s) will be updated:

# CRAN -----------------------------------------------------------------------
- base64enc     [* -> 0.1-3]
- bslib         [* -> 0.4.2]
- cachem        [* -> 1.0.7]
- cli           [* -> 3.6.1]
- digest        [* -> 0.6.31]
- ellipsis      [* -> 0.3.2]
- evaluate      [* -> 0.20]
- fastmap       [* -> 1.1.1]
- fontawesome   [* -> 0.5.1]
- fs            [* -> 1.6.2]
- glue          [* -> 1.6.2]
- highr         [* -> 0.10]
- htmltools     [* -> 0.5.5]
- jquerylib     [* -> 0.1.4]
- jsonlite      [* -> 1.8.4]
- knitr         [* -> 1.42]
- lifecycle     [* -> 1.0.3]
- magrittr      [* -> 2.0.3]
- memoise       [* -> 2.0.1]
- mime          [* -> 0.12]
- R6            [* -> 2.5.1]
- rappdirs      [* -> 0.3.3]
- rlang         [* -> 1.1.1]
- rmarkdown     [* -> 2.21]
- sass          [* -> 0.4.5]
- stringi       [* -> 1.7.12]
- stringr       [* -> 1.5.0]
- tinytex       [* -> 0.45]
- vctrs         [* -> 0.6.2]
- xfun          [* -> 0.39]
- yaml          [* -> 2.3.7]

fixes #3

[lnnrtwttkhn]

I've also added some instructions regarding renv to the README.md, see 7c67692

[HeidiSeibold]

Wow, nice. Thank you!