rebar3/systest/all_SUITE_data/compile_deps/rebar.config

{deps, [
        {fake_dep, {localdep, "fake_dep"}}
       ]}.

{plugins, [{rebar_localdep,
            {git, "https://github.com/alinpopa/rebar3-localdep-plugin.git",
             {branch, "master"}}}]}.