Use singular 'key' key

Author: rickhanlonii

.circleci/config.yml

@@ -54,7 +54,7 @@ jobs:
           command: node --version
       - restore_cache:
           name: Restore yarn cache
-          keys: v2-node-{{ arch }}-{{ checksum "yarn.lock" }}-yarn
+          key: v2-node-{{ arch }}-{{ checksum "yarn.lock" }}-yarn
       - run:
           name: Install Packages
           command: yarn --frozen-lockfile --cache-folder ~/.cache/yarn