Still search and get from git?

```
===> Fetching rebar3_path_deps v0.4.0
===> Downloaded package, caching at /root/.cache/rebar3/hex/hexpm/packages/rebar3_path_deps-0.4.0.tar
===> Compiling rebar3_path_deps
===> Verifying dependencies...
===> Fetching emqx (from {git,"https://github.com/emqx/emqx",{path,"emqx"}})
===> WARNING: It is recommended to use {branch, Name}, {tag, Tag} or {ref, Ref}, otherwise updating the dep may not work as expected.
===> Failed to fetch and copy dep: {git,"https://github.com/emqx/emqx",
{path,"emqx"}}
make: *** [emqx] Error 1

```

Start by reproducing the shown failure while fetching the emqx Git dependency with its path declaration, then inspect how rebar3_path_deps handles Git dependencies. Done means the dependency fetch and copy succeeds, or the supported behavior and limitation are clearly established.

Written by the indexing model from the issue text.