remove yarn step from ci

there are no dependencies!

Author: chearon

.github/workflows/node.js.yml

@@ -12,6 +12,5 @@ jobs:
       uses: actions/setup-node@v1
       with:
         node-version: ${{ matrix.node-version }}
-    - run: yarn --frozen-lockfile
     - run: yarn build
     - run: yarn test