consider using renv

[laijasmine]

Since we re-install awardsBot to the server with every new release, it might be useful to have something like renv in place so the versions of packages used locally to test are consistent with what will be installed on awards bot - https://rstudio.github.io/renv/articles/renv.html.

• Having the minimum package versions in the description only solves part of the problem.
• There are some packages like slackr that are being worked on regularly might have breaking changes that we might not have been keeping up with all the time - https://github.com/mrkaye97/slackr/releases/tag/v3.0.0
• Easier for someone new picking up awardsBot for the first time