Replaced yarn with npm

Author: Kameshwaran

.circleci/config.yml

@@ -26,12 +26,12 @@ jobs:
           # fallback to using the latest cache if no exact match is found
           - v1-dependencies-
 
-      - run: yarn install && cd docs && yarn install
+      - run: npm install && cd docs && npm install
 
       - save_cache:
           paths:
             - node_modules
           key: v1-dependencies-{{ checksum "package.json" }}
 
       # run tests!
-      - run: yarn run lint
+      - run: npm run lint