the latest npm does not support node 16 anymore

Author: gfx

.github/workflows/ci.yml

@@ -25,7 +25,6 @@ jobs:
         cache: npm
         node-version: ${{ matrix.node-version }}
 
-    - run: npm install -g npm
     - run: npm install -g nyc codecov
     - run: npm ci
     - run: npm run test:cover