chore(deps): update circleci/node:8.12.0 docker digest to 2c84f34

Author: renovate-bot

.circleci/config.yml

@@ -19,7 +19,7 @@ jobs:
     build:
         working_directory: ~/guesswork
         docker:
-            - image: circleci/node:8.12.0@sha256:a44f73432310d38236bec7a6b7acc1eaa57fa56171e4e698d264bbbaaa5f1b97
+            - image: circleci/node:8.12.0@sha256:2c84f344eb3916f3fe6808a5b2cfc503e353f95cbc19b3b04fa36b3aa84581e8
         steps:
             - checkout
             - run:
@@ -45,7 +45,7 @@ jobs:
     release:
         working_directory: ~/guesswork
         docker:
-            - image: circleci/node:8.12.0@sha256:a44f73432310d38236bec7a6b7acc1eaa57fa56171e4e698d264bbbaaa5f1b97
+            - image: circleci/node:8.12.0@sha256:2c84f344eb3916f3fe6808a5b2cfc503e353f95cbc19b3b04fa36b3aa84581e8
         steps:
             - checkout
             - run: npm install