Dockerfile in maltese-0.8.12 vs Dockerfile in maltese-0.8.13

@@ -9,8 +9,8 @@
 # Update installed APT packages, clean up APT when done.
 RUN apt-get update && apt-get upgrade -y -o Dpkg::Options::="--force-confold" && \
     apt-get clean && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
 
 # Install maltese gem
-RUN /sbin/setuser app gem install maltese -v 0.8.12
+RUN /sbin/setuser app gem install maltese -v 0.8.13
 
 CMD maltese sitemap --sitemap_bucket $SITEMAP_BUCKET