chore: start testing on node 10

.circleci/config.yml

@@ -31,12 +31,15 @@ workflows:
           filters: *release_tags
       - node9:
           filters: *release_tags
+      - node10:
+          filters: *release_tags
       - publish_npm:
           requires:
             - node4
             - node6
             - node8
             - node9
+            - node10
           filters:
             branches:
               ignore: /.*/
@@ -63,10 +66,15 @@ jobs:
       - image: node:9
         user: node
     <<: *unit_tests
+  node10:
+    docker:
+      - image: node:10
+        user: node
+    <<: *unit_tests
 
   publish_npm:
     docker:
-      - image: node:8
+      - image: node10
         user: node
     steps:
       - checkout
@@ -78,4 +86,4 @@ jobs:
           command: npm install
       - run:
           name: Publish the module to npm.
-          command: npm publish
+          command: npm publish