install_latest: Update latest ggeffects-version from R-universe (GitHub) or CRAN
Description
This function can be used to install the latest package version of ggeffects,
either the development version (from R-universe/GitHub) or the current
version from CRAN.
Character. Either "development" or "cran". If "cran",
ggeffects will be installed from the default CRAN mirror returned by
getOption("repos")['CRAN']. If "development" (the default), ggeffects
is installed from the r-universe repository (https://strengejacke.r-universe.dev/).
force
Logical, if FALSE, the update will only be installed if a newer
version is available. Use force=TRUE to force installation, even if the
version number for the locally installed package is identical to the latest
development-version. Only applies when source="development".