PIPELINE: fix Dockerfile

.docker/Dockerfile

@@ -8,7 +8,8 @@ RUN apt-get update && \
     python3-pip \
     tox \
     -y
-RUN echo ${PYLIB}
+ARG PYLIB
+RUN echo "PYLIB=${PYLIB}"
 COPY .docker/wait-for-it.sh /wait-for-it.sh
 ADD https://gitlab.indiscale.com/api/v4/projects/97/repository/commits/${PYLIB} \
     pylib_version.json