Test using npm@8

Author: novemberborn

.github/workflows/ci.yml

@@ -20,6 +20,7 @@ jobs:
       - uses: actions/setup-node@v2
         with:
           node-version: ${{ matrix.node-version }}
+      - run: npm install --global npm@8
       - run: npm install --no-audit
       - run: npm test
       - uses: codecov/codecov-action@v2