Update Circle CI config to use Node.js 12.13.0.

b0cfa2abad

.circleci/config.yml

@@ -61,7 +61,7 @@ run_save_node_bin: &run_save_node_bin
 build_machine_environment: &build_machine_environment
   # Specify that we want an actual machine (ala Circle 1.0), not a Docker image.
   docker:
-    - image: meteor/circleci:android-27-node-8
+    - image: meteor/circleci:android-27-node-12
   environment:
     # This multiplier scales the waitSecs for selftests.
     TIMEOUT_SCALE_FACTOR: 8
@@ -669,7 +669,7 @@ jobs:
   Docs:
     docker:
       # This Node version should match that in the meteor/docs CircleCI config.
-      - image: circleci/node:8
+      - image: meteor/circleci:android-27-node-12
     environment:
       CHECKOUT_METEOR_DOCS: /home/circleci/test_docs
     steps: