Update Dockerfile

Dockerfile

 FROM netboxcommunity/netbox
 ENV NAPALM_USERNAME netbox-napalm
 
-RUN apk add git && pip3 install --upgrade napalm cffi napalm-dellos10 netbox-qrcode && \
+RUN apk add git && pip3 install --upgrade napalm cffi napalm-dellos10 py3-setuptools
+RUN easy_install pillow
+RUN apk add netbox-qrcode && \
     echo "PLUGINS = ['netbox_qrcode']" >> /etc/netbox/config/configuration.py