Fix poetry install in docker image

Dockerfile

@@ -2,7 +2,7 @@ FROM nginx:1.19.0-alpine
 
 RUN apk update && apk add bash git python3 make tzdata curl && rm -rf /var/cache/apk/* 
 #RUN python3 -m pip install requests mistune pygments toml
-RUN curl -sSL https://raw.githubusercontent.com/python-poetry/poetry/master/get-poetry.py | python3 -
+RUN curl -sSL https://install.python-poetry.org | POETRY_VERSION=1.2.0 python3 -
 COPY docker/nginx.conf /etc/nginx/nginx.conf
 
 # install locales