install js depenedencies globally

Dockerfile

@@ -19,7 +19,8 @@ COPY files/start.sh /start.sh
 COPY files/requirements.txt requirements.txt
 RUN pip3 install wheel
 RUN pip3 install -r requirements.txt
-RUN npm install cssnano postcss postcss-cssnext postcss-import postcss-preset-env
+RUN npm install -g npm@latest
+RUN npm install -g cssnano postcss postcss-cssnext postcss-import postcss-preset-env
 
 # Cleanup
 RUN apt-get autoremove --yes $build_dependencies && apt-get autoremove --yes && \