FIX: Fixing pipeline.

test/docker/Dockerfile

 FROM debian:10
-RUN echo "deb http://deb.debian.org/debian buster-backports main" >> /etc/apt/sources.list \
+ADD node_gpg.asc /etc/apt/
+RUN  apt-get update \
+    && apt-get install -y gnupg ca-certificates\
+    && apt-key add /etc/apt/node_gpg.asc \
+    && echo "deb http://deb.debian.org/debian buster-backports main" >> /etc/apt/sources.list \
+    && echo "deb https://deb.nodesource.com/node_14.x buster main" >> /etc/apt/sources.list \
     && apt-get update \
     && apt-get install -y \
-      firefox-esr gettext-base python3-pip \
+      firefox-esr gettext-base pylint3 python3-pip \
       python3-httpbin git curl x11-apps xvfb unzip \
-    && apt-get install -y -t buster-backports \
-      npm
+      nodejs # Don't install `npm` (Debian), it conflicts with the `nodejs` (Node) package \
+    && apt-get install -f
 
 RUN pip3 install pylint pytest
 RUN pip3 install caosdb