update docs deps and dev-cluster node to 8.x
diff --git a/dev-cluster/Dockerfile b/dev-cluster/Dockerfile
index c89c104..14df4b1 100644
--- a/dev-cluster/Dockerfile
+++ b/dev-cluster/Dockerfile
@@ -84,17 +84,17 @@
     libmozjs185-dev \
     python-setuptools \ 
     python-pip \
+    python-sphinx \
     python-wheel
 
-RUN pip install \
-    sphinx \
+RUN pip install --upgrade \
     sphinx_rtd_theme
 
 # Node is special
 RUN set -ex; \
     curl -s https://deb.nodesource.com/gpgkey/nodesource.gpg.key | apt-key add -; \
-    echo 'deb https://deb.nodesource.com/node_6.x stretch main' > /etc/apt/sources.list.d/nodesource.list; \
-    echo 'deb-src https://deb.nodesource.com/node_6.x stretch main' >> /etc/apt/sources.list.d/nodesource.list; \
+    echo 'deb https://deb.nodesource.com/node_8.x stretch main' > /etc/apt/sources.list.d/nodesource.list; \
+    echo 'deb-src https://deb.nodesource.com/node_8.x stretch main' >> /etc/apt/sources.list.d/nodesource.list; \
     apt-get update -y && apt-get install -y nodejs; \
     npm install -g grunt-cli
 
diff --git a/dev/Dockerfile b/dev/Dockerfile
index 4b5b2af..24db534 100644
--- a/dev/Dockerfile
+++ b/dev/Dockerfile
@@ -86,10 +86,10 @@
     libmozjs185-dev \
     python-setuptools \ 
     python-pip \
+    python-sphinx \
     python-wheel
 
-RUN pip install \
-    sphinx \
+RUN pip install --upgrade \
     sphinx_rtd_theme
 
 # Node is special