Add -y flag to apt-get build-dep

Author: hturner

Dockerfile

@@ -10,7 +10,7 @@ RUN sed -i.bak "/^#.*deb-src.*universe$/s/^# //g" /etc/apt/sources.list \
     && add-apt-repository --enable-source --yes "ppa:marutter/rrutter4.0" \
     && wget -qO- https://cloud.r-project.org/bin/linux/ubuntu/marutter_pubkey.asc | tee -a /etc/apt/trusted.gpg.d/cran_ubuntu_key.asc \
     && apt-get update \
-    && apt-get build-dep r-base-dev \
+    && apt-get build-dep -y r-base-dev \
     && apt-get install -y r-base-dev \
     && rm -rf /var/lib/apt/lists/*