ci: update circle ci conf

Author: dherges

.circleci/config.yml

@@ -18,16 +18,14 @@ jobs:
       # Download and cache dependencies
       - restore_cache:
           keys:
-          - v1-dependencies-{{ checksum "package.json" }}
-          # fallback to using the latest cache if no exact match is found
-          - v1-dependencies-
+          - v1-dependencies-{{ checksum "yarn.lock" }}
 
       - run: yarn install
 
       - save_cache:
           paths:
             - node_modules
-          key: v1-dependencies-{{ checksum "package.json" }}
+          key: v1-dependencies-{{ checksum "yarn.lock" }}
 
       # run tests!
       - run: xvfb-run -a yarn ci:e2e