use more memory for Node 6 to prevent OOMs

Author: thymikee

.circleci/config.yml

@@ -38,7 +38,7 @@ jobs:
     steps:
       - checkout
       - restore-cache: *restore-cache
-      - run: yarn --no-progress --frozen-lockfile --ignore-engines
+      - run: node --max-old-space-size=4096 .yarn/releases/yarn-1.15.0.js --no-progress --frozen-lockfile --ignore-engines
       - save-cache: *save-cache
       - run:
           # react-native does not work with node 6