Adds a CODE_OF_CONDUCT.md file to the active project and lists in
.Rbuildignore, in the case of a package. The goal of a code of conduct is
to foster an environment of inclusiveness, and to explicitly discourage
inappropriate behaviour. The template comes from
http://contributor-covenant.org, version 1:
http://contributor-covenant.org/version/1/0/0/.
use_code_of_conduct(path = NULL)Path of the directory to put CODE_OF_CONDUCT.md in, relative to
the active project. Passed along to use_directory(). Default is to locate
at top-level, but .github/ is also common.