misc: Replace deprecated uvicorn.workers with uvicorn-worker

According to the `uvicorn` docs [1], the `uvicorn.workers.UvicornWorker`
class is deprecated and replaced by the `uvicorn-worker` package [2].

[1] https://www.uvicorn.org/deployment/#gunicorn
[2] https://github.com/Kludex/uvicorn-worker

docker/init_scripts/init

@@ -88,10 +88,9 @@ start_bin_gunicorn() {
 		--bind=unix:/tmp/gunicorn.sock \
 		--pid=/tmp/gunicorn.pid \
 		--forwarded-allow-ips="*" \
-		--worker-class uvicorn.workers.UvicornWorker \
+		--worker-class uvicorn_worker.UvicornWorker \
 		--workers "${WEB_CONCURRENCY:-${DEFAULT_WEB_CONCURRENCY:-1}}" \
 		--error-logfile - \
-		--error-logfile - \
 		--log-config /etc/gunicorn/logging.conf \
 		main:app &
 }