chore(deps): update node:8.16.0 docker digest to 51e3a82

Author: renovate-bot

.circleci/config.yml

@@ -6,7 +6,7 @@ machine:
 jobs:
   build:
     docker:
-      - image: node:8.16.0@sha256:c671dc2c9148c8f4a5c2ae2cd8b3524179a44dc35c924a947ce71c23c0529c12
+      - image: node:8.16.0@sha256:51e3a82bc141a4646b86acc76f52b7c2ef72a5050d97788cc0bd41e029f0d711
     environment:
       - NPM_CONFIG_LOGLEVEL: warn
     working_directory: ~/repo