Update CI docker image

packages/react-navigation/.circleci/config.yml

@@ -2,7 +2,7 @@ version: 2
 jobs:
   build:
     docker:
-      - image: reactcommunity/node-ci:7.10.0-1 # custom image -- includes ocaml, libelf1, Yarn
+      - image: reactcommunity/node-ci:8.4.0-0 # custom image -- includes ocaml, libelf1, Yarn
     parallelism: 2
     working_directory: ~/react-navigation
     steps:

packages/react-navigation/scripts/build-push-docker.sh

@@ -2,5 +2,5 @@
 
 set -eo pipefail
 
-docker build -t reactcommunity/node-ci:7.10.0-1 -f ./ci.Dockerfile .
-docker push reactcommunity/node-ci:7.10.0-1
+docker build -t reactcommunity/node-ci:8.4.0-0 -f ./ci.Dockerfile .
+docker push reactcommunity/node-ci:8.4.0-0

packages/react-navigation/scripts/ci.Dockerfile

@@ -1,10 +1,10 @@
-FROM node:7.10.0
+FROM node:8.4.0
 
 RUN apt-get update -y && \
     apt-get install -y ocaml libelf1 && \
     rm -rf /var/lib/apt/lists/* && \
     curl -o- -L https://yarnpkg.com/install.sh | bash && \
-    npm install -g exp
+    yarn global add exp
     
 RUN git clone https://github.com/facebook/watchman.git \
     && cd watchman \