Remove empty line and comment in Dockerfile
Remove empty line and comment in Dockerfile

Warning received when starting up that future versions of docker may
cause the RUN command to fail when including empty continuation lines:

 Empty continuation line found in:
    RUN set -exu     && apt-get update     && apt-get install -y libgdal-dev=2.1.2+dfsg-5 postgresql-client     && rm -rf /var/lib/apt/lists/*     && wget -O /usr/local/bin/gosu "https://github.com/tianon/gosu/releases/download/$GOSU_VERSION/gosu-$(dpkg --print-architecture)"     && chmod +x /usr/local/bin/gosu     && gosu nobody true
[WARNING]: Empty continuation lines will become errors in a future release.

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