Update CircleCI config

Author: mdeboer

.circleci/config.yml

@@ -1,17 +1,31 @@
 version: 2
 
+shared: &shared
+  steps:
+    - checkout
+    - run: yarn
+    - run: yarn test:ci
+
 jobs:
-  test:
+  test-node-10:
+    docker:
+      - image: node:10
+    <<: *shared
+
+  test-node-12:
     docker:
-      - image: node:8
-    steps:
-      - checkout
+      - image: node:12
+    <<: *shared
 
-      - run: yarn
-      - run: yarn test:ci
+  test-node-13:
+    docker:
+      - image: node:13
+    <<: *shared
 
 workflows:
   version: 2
-  test-publish:
+  test:
     jobs:
-      - test
+      - test-node-10
+      - test-node-12
+      - test-node-13