Remove fixed PUBLIC_URL in Dockerfile

Change-Id: Ifb2e41f02f6568fd80fe9de4c76b633236ceffe4

Dockerfile

@@ -1,14 +1,13 @@
 # Builder
 FROM node:lts as builder
 
-ARG PUBLIC_URL=/
 ARG REACT_APP_SERVER
 
 WORKDIR /src
 
 COPY . /src
 RUN yarn --network-timeout=300000 install
-RUN PUBLIC_URL=$PUBLIC_URL REACT_APP_SERVER=$REACT_APP_SERVER yarn build
+RUN REACT_APP_SERVER=$REACT_APP_SERVER yarn build
 
 
 # App