OSError: Yajl cannot be found.

MacOS:

```
python -m openaoe.main -f openaoe/backend/config/config-template.yaml
Traceback (most recent call last):
File "/Users/zhangsongyang/miniconda3/envs/openaoe/lib/python3.8/runpy.py", line 194, in _run_module_as_main
return _run_code(code, main_globals, None,
File "/Users/zhangsongyang/miniconda3/envs/openaoe/lib/python3.8/runpy.py", line 87, in _run_code
exec(code, run_globals)
File "/Users/zhangsongyang/Projects/OpenAOE/openaoe/main.py", line 10, in
from openaoe.backend.api.route_google import router as google
File "/Users/zhangsongyang/Projects/OpenAOE/openaoe/backend/api/route_google.py", line 4, in
from openaoe.backend.service.service_google import palm_chat_svc, Gemma
File "/Users/zhangsongyang/Projects/OpenAOE/openaoe/backend/service/service_google.py", line 4, in
from jsonstreamer import ObjectStreamer
File "/Users/zhangsongyang/miniconda3/envs/openaoe/lib/python3.8/site-packages/jsonstreamer/__init__.py", line 9, in
from jsonstreamer.jsonstreamer import JSONStreamer, ObjectStreamer
File "/Users/zhangsongyang/miniconda3/envs/openaoe/lib/python3.8/site-packages/jsonstreamer/jsonstreamer.py", line 14, in
from .yajl.parse import YajlParser, YajlListener, YajlError
File "/Users/zhangsongyang/miniconda3/envs/openaoe/lib/python3.8/site-packages/jsonstreamer/yajl/parse.py", line 31, in
yajl = load_lib()
File "/Users/zhangsongyang/miniconda3/envs/openaoe/lib/python3.8/site-packages/jsonstreamer/yajl/parse.py", line 28, in load_lib
raise OSError('Yajl cannot be found.')
OSError: Yajl cannot be found.
```