Update uvicorn-worker from 0.2.0 to 0.3.0 (cookiecutter#5607)

Author: pyup-bot

{{cookiecutter.project_slug}}/requirements/base.txt

@@ -24,7 +24,7 @@ flower==2.0.1  # https://github.com/mher/flower
 {%- endif %}
 {%- if cookiecutter.use_async == 'y' %}
 uvicorn[standard]==0.34.0  # https://github.com/encode/uvicorn
-uvicorn-worker==0.2.0  # https://github.com/Kludex/uvicorn-worker
+uvicorn-worker==0.3.0  # https://github.com/Kludex/uvicorn-worker
 {%- endif %}
 
 # Django