Using activate() will:
Load the requested project via load(),
Add source("renv/init.R") to the project .Rprofile, thereby
instructing newly-launched R sessions to automatically load the
current project.
Normally, activate() is called as part of init() when a project
is first initialized. However, activate() can be used to activate
(or re-activate) an renv project -- for example, if the project was shared
without the auto-loader included in the project .Rprofile, or because
that project was previously deactivated (via deactivate()).