Modify port in Dockerfile

Author: therealthaibinh

Dockerfile

@@ -1,6 +1,7 @@
 FROM python:3.7.7-slim-buster
 ENV PARAMETERS=./defaults/webapp.cfg
 ENV PPE_EXCEL=./defaults/PPE_Usage_Draft_CC_modifications_v2.xlsx
+ENV STREAMLIT_SERVER_PORT=$PORT
 WORKDIR /app
 COPY README.md .
 COPY setup.cfg .